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Zhang L, Li G, OuYang Z, Yang R, Gao Y, Cao X, Bányai I, Shi X, Guo R. Intelligent design of iron-doped LDH nanosheets for cooperative chemo-chemodynamic therapy of tumors†. Biomater Sci 2022; 10:2029-2039. [DOI: 10.1039/d2bm00102k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chemodynamic therapy (CDT) has received increasing attention due to its unique tumor microenvironment (TME) responsiveness and minimal adverse side effects, but the therapeutic effect of CDT alone is always limited...
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Tóth-Molnár E, Lihi N, Gál GT, De S, Bombicz P, Bányai I, Szikra D, Dénes E, Tircsó G, Tóth I, Kálmán FK. Exploring Cyclic Aminopolycarboxylate Ligands for Sb(III) Complexation: PCTA and Its Derivatives as a Promising Solution. Inorg Chem 2021; 60:14253-14262. [PMID: 34463492 DOI: 10.1021/acs.inorgchem.1c01765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In recent years Auger electron emitters have been suggested as promising candidates for radiotherapy with no side effects in cancer treatment. In this work we report a detailed coordination chemistry study of [Sb(PCTA)] (PCTA: 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid), a macrocyclic aminopolycarboxylate-type complex of antimony(III), whose 119Sb isotope could be a suitable low-energy electron emitter for radiotherapy. The thermodynamic stability of the chelate obtained by pH-potentiometry and UV-vis spectrophotometry is high enough (log K[Sb(PCTA)] = 23.2(1)) to prevent the hydrolysis of the metal ion near physiological pH. The formation of [Sb(PCTA)] is confirmed by NMR and electrospray ionization mass spectrometry measurements in solution; furthermore, the structure of [Sb(PCTA)]·NaCl·3H2O and [Sb(PCTA)]·HCl·3H2O is described by X-ray and density functional theory calculations. Consequently, the [Sb(PCTA)] is the first thermodynamically stable antimony(III) complex bearing polyamino-polycarboxylate macrocyclic platform. Our results demonstrate the potential of rigid (pyclen derivative) ligands as chelators for future applications of Sb(III) in a targeted radiotherapy based on the 119Sb isotope.
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Affiliation(s)
- Enikő Tóth-Molnár
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Norbert Lihi
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Gyula Tamás Gál
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Sourav De
- Research Laboratory of Chemical Crystallography, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Petra Bombicz
- Research Laboratory of Chemical Crystallography, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - István Bányai
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Dezső Szikra
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, University of Debrecen, H-4032 Debrecen, Hungary
| | - Eleonóra Dénes
- Centre of Supramolecular Organic and Organometallic Chemistry, Department of Chemistry, Babeş-Bolyai University, RO-400028 Cluj-Napoca, Romania
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Imre Tóth
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary.,Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
| | - Ferenc Krisztián Kálmán
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, H-4032 Debrecen, Hungary
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3
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Song C, Gao Y, Chen J, Wang L, Bányai I, Shen M, Shi X. Physicochemical aspects of zwitterionic core-shell tecto dendrimers characterized by a thorough NMR investigation. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Ma T, Yang P, Parris JM, Csupász T, Li MX, Bányai I, Tóth I, Lin Z, Kortz U. Indium in Polyoxopalladate(II) Chemistry: Synthesis of All-Acetate-Capped [InPd 12O 8(OAc) 16] 5- and Controlled Transformation to Phosphate-Capped Double-Cube and Monocube. Inorg Chem 2019; 58:15864-15871. [PMID: 31725279 DOI: 10.1021/acs.inorgchem.9b02282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have prepared the indium(III)-centered, all-acetate-capped polyoxopalladate(II) nanocube [InPd12O8(OAc)16]5- (InPd12Ac16), which can be further used as precursor to form the phosphate-capped (i) double-cube [In2Pd23O17(OH)(PO4)12(PO3OH)]21- (In2Pd23P13) and (ii) monocube [InPd12O8(PO4)8]13- (InPd12P8). All three novel polyoxopalladates (POPs) were synthesized using conventional one-pot techniques in aqueous solution and characterized in the solid state (single-crystal XRD, IR, elemental analysis), in solution (115In, 31P, and 13C NMR), and in the gas phase (ESI-MS).
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Affiliation(s)
- Tian Ma
- Department of Life Sciences and Chemistry , Jacobs University , Campus Ring 1 , 28759 Bremen , Germany
| | - Peng Yang
- Department of Life Sciences and Chemistry , Jacobs University , Campus Ring 1 , 28759 Bremen , Germany
| | - Jaclyn M Parris
- Department of Life Sciences and Chemistry , Jacobs University , Campus Ring 1 , 28759 Bremen , Germany
| | - Tibor Csupász
- Department of Inorganic and Analytical Chemistry and Department of Physical Chemistry , University of Debrecen , Egyetem tér 1 , 4032 Debrecen , Hungary
| | - Ming-Xing Li
- Department of Chemistry, College of Sciences , Shanghai University , Shanghai 200444 , P.R. China
| | - István Bányai
- Department of Inorganic and Analytical Chemistry and Department of Physical Chemistry , University of Debrecen , Egyetem tér 1 , 4032 Debrecen , Hungary
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry and Department of Physical Chemistry , University of Debrecen , Egyetem tér 1 , 4032 Debrecen , Hungary
| | - Zhengguo Lin
- Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering , Beijing Institute of Technology , Beijing 100081 , P.R. China
| | - Ulrich Kortz
- Department of Life Sciences and Chemistry , Jacobs University , Campus Ring 1 , 28759 Bremen , Germany
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5
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Li D, Fan Y, Shen M, Bányai I, Shi X. Design of dual drug-loaded dendrimer/carbon dot nanohybrids for fluorescence imaging and enhanced chemotherapy of cancer cells. J Mater Chem B 2019; 7:277-285. [DOI: 10.1039/c8tb02723d] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dual drug-loaded dendrimer/CD nanohybrids can be developed for fluorescence imaging and enhanced chemotherapy of cancer cells.
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Affiliation(s)
- Dan Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- International Joint Laboratory for Advanced Fiber and Low-dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - Yu Fan
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- International Joint Laboratory for Advanced Fiber and Low-dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - Mingwu Shen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- International Joint Laboratory for Advanced Fiber and Low-dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
| | - István Bányai
- Department of Physical Chemistry
- University of Debrecen
- H-4032 Debrecen
- Hungary
| | - Xiangyang Shi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- International Joint Laboratory for Advanced Fiber and Low-dimension Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
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6
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Ayass WW, Fodor T, Farkas E, Lin Z, Qasim HM, Bhattacharya S, Mougharbel AS, Abdallah K, Ullrich MS, Zaib S, Iqbal J, Harangi S, Szalontai G, Bányai I, Zékány L, Tóth I, Kortz U. Dithallium(III)-Containing 30-Tungsto-4-phosphate, [Tl 2Na 2(H 2O) 2(P 2W 15O 56) 2] 16-: Synthesis, Structural Characterization, and Biological Studies. Inorg Chem 2018; 57:7168-7179. [PMID: 29873483 DOI: 10.1021/acs.inorgchem.8b00878] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Here we report on the synthesis and structural characterization of the dithallium(III)-containing 30-tungsto -4-phosphate [Tl2Na2(H2O)2{P2W15O56}2]16- (1) by a multitude of solid-state and solution techniques. Polyanion 1 comprises two octahedrally coordinated Tl3+ ions sandwiched between two trilacunary {P2W15} Wells-Dawson fragments and represents only the second structurally characterized, discrete thallium-containing polyoxometalate to date. The two outer positions of the central rhombus are occupied by sodium ions. The title polyanion is solution-stable as shown by 31P and 203/205Tl NMR. This was also supported by Tl NMR spectra simulations including several spin systems of isotopologues with half-spin nuclei (203Tl, 205Tl, 31P, 183W). 23Na NMR showed a time-averaged signal of the Na+ counter cations and the structurally bonded Na+ ions. 203/205Tl NMR spectra also showed a minor signal tentatively attributed to the trithallium-containing derivative [Tl3Na(H2O)2(P2W15O56)2]14-, which could also be identified in the solid state by single-crystal X-ray diffraction. The bioactivity of polyanion 1 was also tested against bacteria and Leishmania.
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Affiliation(s)
- Wassim W Ayass
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | | | | | - Zhengguo Lin
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Hafiz M Qasim
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Saurav Bhattacharya
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Ali S Mougharbel
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Khaled Abdallah
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Matthias S Ullrich
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
| | - Sumera Zaib
- Centre for Advanced Drug Research , COMSATS University Islamabad, Abbottabad Campus , Abbottabad 22060 , Pakistan
| | - Jamshed Iqbal
- Centre for Advanced Drug Research , COMSATS University Islamabad, Abbottabad Campus , Abbottabad 22060 , Pakistan
| | | | - Gábor Szalontai
- NMR Laboratory , University of Pannonia , Egyetem út 10 , 8200 Veszprém , Hungary
| | | | | | | | - Ulrich Kortz
- Department of Life Sciences and Chemistry , Jacobs University , 28759 Bremen , Germany
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7
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Dancs Á, Selmeczi K, Bányai I, Darula Z, Gajda T. Increasing the histidine ‘density’ in tripodal peptides by gradual N -functionalization of tris (2-aminoethyl)amine (tren) with l -histidyl units: The effect on zinc(II) complexes. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.06.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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8
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Zhou B, Wang R, Chen F, Zhao L, Wang P, Li X, Bányai I, Ouyang Q, Shi X, Shen M. 99mTc-Labeled RGD-Polyethylenimine Conjugates with Entrapped Gold Nanoparticles in the Cavities for Dual-Mode SPECT/CT Imaging of Hepatic Carcinoma. ACS Appl Mater Interfaces 2018; 10:6146-6154. [PMID: 29380596 DOI: 10.1021/acsami.7b17107] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the construction and characterization of 99mTc-labeled arginine-glycine-aspartic acid (RGD)-polyethylenimine (PEI) conjugates with entrapped gold nanoparticles in the cavities (RGD-99mTc-Au PENPs) for dual-mode single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of an orthotopic hepatic carcinoma model. In this study, PEI was successively decorated with diethylenetriaminepentaacetic acid, poly(ethylene glycol) (PEG), and PEGylated RGD segments, and was utilized as an effective nanoplatform to entrap Au NPs and to be labeled with 99mTc. We showed that the designed RGD-99mTc-Au PENPs displayed desirable colloidal stability and radiostability, and cytocompatibility in the investigated concentration range, and could be specifically uptaken by αvβ3 integrin-overexpressing liver cancer cells in vitro. In vivo CT and SPECT imaging results indicated that the particles were able to be accumulated within an orthotopic hepatic carcinoma and displayed both CT and SPECT contrast enhancement in the tumor tissue. With the proven biocompatibility in vivo via histological examinations, the designed RGD-99mTc-Au PENPs may be potentially employed as an effective nanoprobe for a highly efficient dual-mode SPECT/CT imaging of various αvβ3 integrin-overexpressing tumors.
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Affiliation(s)
- Benqing Zhou
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
| | - Ruizhi Wang
- Department of Interventional Radiology, Xinhua Hospital affiliated to Shanghai Jiaotong University , Shanghai 200080, P. R. China
| | - Feng Chen
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
| | - Lingzhou Zhao
- Department of Nuclear Medicine, Shanghai General Hospital, School of Medicine, Shanghai Jiaotong University , Shanghai 200080, P. R. China
| | - Peng Wang
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
| | - Xin Li
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
| | - István Bányai
- Department of Physical Chemistry, University of Debrecen , H-4032 Debrecen, Hungary
| | - Qiang Ouyang
- Department of Interventional Radiology, Xinhua Hospital affiliated to Shanghai Jiaotong University , Shanghai 200080, P. R. China
| | - Xiangyang Shi
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
| | - Mingwu Shen
- State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University , Shanghai 201620, P. R. China
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9
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Abstract
Kinetic information that cannot be acquired with other techniques can be obtained by carefully planned and dynamic NMR experiments.
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Affiliation(s)
- István Bányai
- Department of Physical Chemistry
- University of Debrecen
- 4032 Debrecen
- Hungary
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10
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Affiliation(s)
- István Bányai
- Department of Physical Chemistry, University of Debrecen, H-4010 Debrecen, P.O.Box 31, Hungary
| | - István Lakatos
- Research Institute of Applied Earth Sciences, University of Miskolc, P.O.Box 2, H-3515 Miskolc-Egyetemváros, Hungary
| | - Gerhard Meier
- Institute of Complex Systems 3, Jülich Research Center, D-52425 Jülich, Germany
| | - Zoltán Nagy
- Department of Physical Chemistry, University of Debrecen, H-4010 Debrecen, P.O.Box 31, Hungary
| | - Szabolcs Vass
- Research Institute of Applied Earth Sciences, University of Miskolc, P.O.Box 2, H-3515 Miskolc-Egyetemváros, Hungary
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11
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Veres P, Kéri M, Bányai I, Lázár I, Fábián I, Domingo C, Kalmár J. Mechanism of drug release from silica-gelatin aerogel—Relationship between matrix structure and release kinetics. Colloids Surf B Biointerfaces 2017; 152:229-237. [DOI: 10.1016/j.colsurfb.2017.01.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/04/2017] [Accepted: 01/12/2017] [Indexed: 11/15/2022]
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12
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Lihi N, Sanna D, Bányai I, Várnagy K, Sóvágó I. Unusual binding modes in the copper(ii) and palladium(ii) complexes of peptides containing both histidyl and cysteinyl residues. NEW J CHEM 2017. [DOI: 10.1039/c6nj03735f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The change of the histidine in the peptide chain provides unusual binding behavior of albumin related peptides.
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Affiliation(s)
- Norbert Lihi
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Daniele Sanna
- Istituto CNR di Chimica Biomolecolare
- I-07040 Sassari
- Italy
| | - István Bányai
- Department of Physical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Katalin Várnagy
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Imre Sóvágó
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
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13
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Kéri M, Nagy Z, Novák L, Szarvas E, Balogh LP, Bányai I. Beware of phosphate: evidence of specific dendrimer–phosphate interactions. Phys Chem Chem Phys 2017; 19:11540-11548. [DOI: 10.1039/c7cp00875a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
G5 PAMAM dendrimers interact with phosphate ions by forming H-bonds with tertiary amino groups in neutral medium.
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Affiliation(s)
- Mónika Kéri
- Department of Physical Chemistry
- University of Debrecen
- Hungary
| | - Zoltán Nagy
- Department of Physical Chemistry
- University of Debrecen
- Hungary
| | - Levente Novák
- Department of Physical Chemistry
- University of Debrecen
- Hungary
| | - Edit Szarvas
- Department of Physical Chemistry
- University of Debrecen
- Hungary
| | | | - István Bányai
- Department of Physical Chemistry
- University of Debrecen
- Hungary
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14
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Bányai I, Farkas I, Tóth I. Simple (17) O NMR method for studying electron self-exchange reaction between UO2 (2+) and U(4+) aqua ions in acidic solution. Magn Reson Chem 2016; 54:444-450. [PMID: 25854521 DOI: 10.1002/mrc.4235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/10/2015] [Accepted: 02/19/2015] [Indexed: 06/04/2023]
Abstract
(17) O NMR spectroscopy is proven to be suitable and convenient method for studying the electron exchange by following the decrease of (17) O-enrichment in U(17) OO(2+) ion in the presence of U(4+) ion in aqueous solution. The reactions have been performed at room temperature using I = 5 M ClO4 (-) ionic medium in acidic solutions in order to determine the kinetics of electron exchange between the U(4+) and UO2 (2+) aqua ions. The rate equation is given as R = a[H(+) ](-2) + R', where R' is an acid independent parallel path. R' depends on the concentration of the uranium species according to the following empirical rate equation: R' = k1 [UO(2 +) ](1/2) [U(4 +) ](1/2) + k2 [UO(2 +) ](3/2) [U(4 +) ](1/2) . The mechanism of the inverse H(+) concentration-dependent path is interpreted as equilibrium formation of reactive UO2 (+) species from UO2 (2+) and U(4+) aqua ions and its electron exchange with UO2 (2+) . The determined rate constant of this reaction path is in agreement with the rate constant of UO2 (2+) -UO2 (+) , one electron exchange step calculated by Marcus theory, match the range given experimentally of it in an early study. Our value lies in the same order of magnitude as the recently calculated ones by quantum chemical methods. The acid independent part is attributed to the formation of less hydrolyzed U(V) species, i.e. UO(3+) , which loses enrichment mainly by electron exchange with UO2 (2+) ions. One can also conclude that (17) O NMR spectroscopy, or in general NMR spectroscopy with careful kinetic analysis, is a powerful tool for studying isotope exchange reactions without the use of sophisticated separation processes. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- István Bányai
- Department of Colloid and Environmental Chemistry, University of Debrecen (UD), Debrecen, Hungary
| | - Ildikó Farkas
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry, University of Debrecen (UD), Debrecen, Hungary
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15
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Abstract
The internal spatial structures of PEGylated polyethylenimine-entrapped gold nanoparticles can be effectively analyzed via advanced NMR techniques.
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Affiliation(s)
- Benqing Zhou
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
| | - Mingwu Shen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
| | - István Bányai
- Department of Colloid and Environmental Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Xiangyang Shi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials
- College of Chemistry
- Chemical Engineering and Biotechnology
- Donghua University
- Shanghai 201620
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16
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Fodor T, Bányai I, Bényei A, Platas-Iglesias C, Purgel M, Horváth GL, Zékány L, Tircsó G, Tóth I. [Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex. Inorg Chem 2015; 54:5426-37. [PMID: 25977977 DOI: 10.1021/acs.inorgchem.5b00458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔ Δ(δδδδ) interconversion.
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Affiliation(s)
| | | | | | - Carlos Platas-Iglesias
- ∥Departamento de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira-Rúa da Fraga 10, 15008 A Coruña, Spain
| | - Mihály Purgel
- ⊥MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Gábor L Horváth
- #Institute of Innate Immunity, University Hospital, University of Bonn, 53127 Bonn, Germany
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17
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Affiliation(s)
- Mónika Kéri
- Department
of Colloid and Environmental Chemistry, University of Debrecen, Debrecen, Hungary
| | | | | | - István Bányai
- Department
of Colloid and Environmental Chemistry, University of Debrecen, Debrecen, Hungary
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18
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Kalmár J, Kéri M, Erdei Z, Bányai I, Lázár I, Lente G, Fábián I. The pore network and the adsorption characteristics of mesoporous silica aerogel: adsorption kinetics on a timescale of seconds. RSC Adv 2015. [DOI: 10.1039/c5ra21353c] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pore network and adsorption properties of mesoporous silica aerogel: a mechanistic study on the timescale of seconds.
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Affiliation(s)
- József Kalmár
- MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group
- Hungary
| | - Mónika Kéri
- Department of Colloid and Environmental Chemistry
- University of Debrecen
- Hungary
| | - Zsolt Erdei
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Hungary
| | - István Bányai
- Department of Colloid and Environmental Chemistry
- University of Debrecen
- Hungary
| | - István Lázár
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Hungary
| | - Gábor Lente
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Hungary
| | - István Fábián
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Hungary
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19
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Lihi N, Grenács Á, Timári S, Turi I, Bányai I, Sóvágó I, Várnagy K. Zinc(ii) and cadmium(ii) complexes of N-terminally free peptides containing two separate cysteinyl binding sites. NEW J CHEM 2015. [DOI: 10.1039/c5nj01677k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The novel synthesized cysteine peptides form stable zinc(ii) and cadmium(ii) complexes; the specific sequence makes possible metal induced amide deprotonation.
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Affiliation(s)
- Norbert Lihi
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Ágnes Grenács
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Sarolta Timári
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Ildikó Turi
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - István Bányai
- Department of Colloid and Environmental Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Imre Sóvágó
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
| | - Katalin Várnagy
- Department of Inorganic and Analytical Chemistry
- University of Debrecen
- Debrecen
- Hungary
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20
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He X, Alves CS, Oliveira N, Rodrigues J, Zhu J, Bányai I, Tomás H, Shi X. RGD peptide-modified multifunctional dendrimer platform for drug encapsulation and targeted inhibition of cancer cells. Colloids Surf B Biointerfaces 2015; 125:82-9. [PMID: 25437067 DOI: 10.1016/j.colsurfb.2014.11.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 10/26/2014] [Accepted: 11/03/2014] [Indexed: 02/08/2023]
Abstract
Development of multifunctional nanoscale drug-delivery systems for targeted cancer therapy still remains a great challenge. Here, we report the synthesis of cyclic arginine-glycine-aspartic acid (RGD) peptide-conjugated generation 5 (G5) poly(amidoamine) dendrimers for anticancer drug encapsulation and targeted therapy of cancer cells overexpressing αvβ3 integrins. In this study, amine-terminated G5 dendrimers were used as a platform to be sequentially modified with fluorescein isothiocyanate (FI) via a thiourea linkage and RGD peptide via a polyethylene glycol (PEG) spacer, followed by acetylation of the remaining dendrimer terminal amines. The developed multifunctional dendrimer platform (G5.NHAc-FI-PEG-RGD) was then used to encapsulate an anticancer drug doxorubicin (DOX). We show that approximately six DOX molecules are able to be encapsulated within each dendrimer platform. The formed complexes are water-soluble, stable, and able to release DOX in a sustained manner. One- and two-dimensional NMR techniques were applied to investigate the interaction between dendrimers and DOX, and the impact of the environmental pH on the release rate of DOX from the dendrimer/DOX complexes was also explored. Furthermore, cell biological studies demonstrate that the encapsulation of DOX within the G5.NHAc-FI-PEG-RGD dendrimers does not compromise the anticancer activity of DOX and that the therapeutic efficacy of the dendrimer/DOX complexes is solely related to the encapsulated DOX drug. Importantly, thanks to the role played by RGD-mediated targeting, the developed dendrimer/drug complexes are able to specifically target αvβ3 integrin-overexpressing cancer cells and display specific therapeutic efficacy to the target cells. The developed RGD peptide-targeted multifunctional dendrimers may thus be used as a versatile platform for targeted therapy of different types of αvβ3 integrin-overexpressing cancer cells.
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Affiliation(s)
- Xuedan He
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal
| | - Carla S Alves
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal
| | - Nilsa Oliveira
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal
| | - João Rodrigues
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal
| | - Jingyi Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, People's Republic of China
| | - István Bányai
- Department of Colloid and Environmental Chemistry, Faculty of Science, University of Debrecen, H4032 Egyetem t.1, Debrecen, Hungary.
| | - Helena Tomás
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal.
| | - Xiangyang Shi
- CQM-Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal; State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, People's Republic of China.
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21
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Zhang M, Guo R, Kéri M, Bányai I, Zheng Y, Cao M, Cao X, Shi X. Impact of Dendrimer Surface Functional Groups on the Release of Doxorubicin from Dendrimer Carriers. J Phys Chem B 2014; 118:1696-706. [DOI: 10.1021/jp411669k] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Mengen Zhang
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
| | - Rui Guo
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
| | - Mónika Kéri
- Department
of Colloid and Environmental Chemistry, Faculty of Science, University of Debrecen, H4032 Egyetem t.1, Debrecen, Hungary
| | - István Bányai
- Department
of Colloid and Environmental Chemistry, Faculty of Science, University of Debrecen, H4032 Egyetem t.1, Debrecen, Hungary
| | - Yun Zheng
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
| | - Mian Cao
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
| | - Xueyan Cao
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
| | - Xiangyang Shi
- College
of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, People’s Republic of China
- CQM-Centro
de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal, Portugal
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22
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Baranyai Z, Uggeri F, Maiocchi A, Giovenzana GB, Cavallotti C, Takács A, Tóth I, Bányai I, Bényei A, Brucher E, Aime S. Equilibrium, Kinetic and Structural Studies of AAZTA Complexes with Ga3+, In3+and Cu2+. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201201108] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kalmár J, Biri B, Lente G, Bányai I, Budimir A, Biruš M, Batinić-Haberle I, Fábián I. Detailed mechanism of the autoxidation of N-hydroxyurea catalyzed by a superoxide dismutase mimic Mn(III) porphyrin: formation of the nitrosylated Mn(II) porphyrin as an intermediate. Dalton Trans 2012; 41:11875-84. [PMID: 22911446 DOI: 10.1039/c2dt31200j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The in vitro autoxidation of N-hydroxyurea (HU) is catalyzed by Mn(III)TTEG-2-PyP(5+), a synthetic water soluble Mn(III) porphyrin which is also a potent mimic of the enzyme superoxide dismutase. The detailed mechanism of the reaction is deduced from kinetic studies under basic conditions mostly based on data measured at pH = 11.7 but also including some pH-dependent observations in the pH range 9-13. The major intermediates were identified by UV-vis spectroscopy and electrospray ionization mass spectrometry. The reaction starts with a fast axial coordination of HU to the metal center of Mn(III)TTEG-2-PyP(5+), which is followed by a ligand-to-metal electron transfer to get Mn(II)TTEG-2-PyP(4+) and the free radical derived from HU (HU˙). Nitric oxide (NO) and nitroxyl (HNO) are minor intermediates. The major pathway for the formation of the most significant intermediate, the {MnNO} complex of Mn(II)TTEG-2-PyP(4+), is the reaction of Mn(II)TTEG-2-PyP(4+) with NO. We have confirmed that the autoxidation of the intermediates opens alternative reaction channels, and the process finally yields NO(2)(-) and the initial Mn(III)TTEG-2-PyP(5+). The photochemical release of NO from the {MnNO} intermediate was also studied. Kinetic simulations were performed to validate the deduced rate constants. The investigated reaction has medical implications: the accelerated production of NO and HNO from HU may be utilized for therapeutic purposes.
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Affiliation(s)
- József Kalmár
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary H-4010, POB-21
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24
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Tircsó G, Kálmán FK, Pál R, Bányai I, Varga TR, Király R, Lázár I, Québatte L, Merbach AE, Tóth É, Brücher E. Lanthanide Complexes Formed with the Tri- and Tetraacetate Derivatives of Bis(aminomethyl)phosphinic Acid: Equilibrium, Kinetic and NMR Spectroscopic Studies. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101299] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Purgel M, Baranyai Z, de Blas A, Rodríguez-Blas T, Bányai I, Platas-Iglesias C, Tóth I. An NMR and DFT Investigation on the Conformational Properties of Lanthanide(III) 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetate Analogues Containing Methylenephosphonate Pendant Arms. Inorg Chem 2010; 49:4370-82. [DOI: 10.1021/ic100177n] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Mihály Purgel
- Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, Egyetem tér 1, Debrecen H-4010, Hungary
- Research group of Homogeneous Catalysis, MTA-DE, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Zsolt Baranyai
- Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, Egyetem tér 1, Debrecen H-4010, Hungary
| | - Andrés de Blas
- Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira, Alejandro de la Sota 1, 15008 A Coruña, Spain
| | - Teresa Rodríguez-Blas
- Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira, Alejandro de la Sota 1, 15008 A Coruña, Spain
| | - István Bányai
- Department of Colloid and Environmental Chemistry, University of Debrecen, P.O. Box 21, Egyetem tér 1, Debrecen H-4010, Hungary
| | - Carlos Platas-Iglesias
- Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira, Alejandro de la Sota 1, 15008 A Coruña, Spain
| | - Imre Tóth
- Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, Egyetem tér 1, Debrecen H-4010, Hungary
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26
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Budimir A, Kalmár J, Fábián I, Lente G, Bányai I, Batinić-Haberle I, Birus M. Water exchange rates of water-soluble manganese(III) porphyrins of therapeutical potential. Dalton Trans 2010; 39:4405-10. [PMID: 20422097 DOI: 10.1039/b926522h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The activation parameters and the rate constants of the water-exchange reactions of Mn(III)TE-2-PyP(5+) (meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin) as cationic, Mn(III)TnHex-2-PyP(5+) (meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin) as sterically shielded cationic, and Mn(III)TSPP(3-) (meso-tetrakis(4-sulfonatophenyl)porphyrin) as anionic manganese(iii) porphyrins were determined from the temperature dependence of (17)O NMR relaxation rates. The rate constants at 298 K were obtained as 4.12 x 10(6) s(-1), 5.73 x 10(6) s(-1), and 2.74 x 10(7) s(-1), respectively. On the basis of the determined entropies of activation, an interchange-dissociative mechanism (I(d)) was proposed for the cationic complexes (DeltaS(double dagger) = approximately 0 J mol(-1) K(-1)) whereas a limiting dissociative mechanism (D) was proposed for Mn(III)TSPP(3-) complex (DeltaS(double dagger) = +79 J mol(-1) K(-1)). The obtained water exchange rate of Mn(III)TSPP(3-) corresponded well to the previously assumed value used by Koenig et al. (S. H. Koenig, R. D. Brown and M. Spiller, Magn. Reson. Med., 1987, 4, 52-260) to simulate the (1)H NMRD curves, therefore the measured value supports the theory developed for explaining the anomalous relaxivity of Mn(III)TSPP(3-) complex. A magnitude of the obtained water-exchange rate constants further confirms the suggested inner sphere electron transfer mechanism for the reactions of the two positively charged Mn(iii) porphyrins with the various biologically important oxygen and nitrogen reactive species. Due to the high biological and clinical relevance of the reactions that occur at the metal site of the studied Mn(iii) porphyrins, the determination of water exchange rates advanced our insight into their efficacy and mechanism of action, and in turn should impact their further development for both diagnostic (imaging) and therapeutic purposes.
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Affiliation(s)
- Ana Budimir
- Faculty of Pharmacy and Biochemistry, University of Zagreb, Ante Kovacića 1, 10000, Zagreb, Croatia
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27
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Purgel M, Takács Z, Jonsson CM, Nagy L, Andersson I, Bányai I, Pápai I, Persson P, Sjöberg S, Tóth I. Glyphosate complexation to aluminium(III). An equilibrium and structural study in solution using potentiometry, multinuclear NMR, ATR-FTIR, ESI-MS and DFT calculations. J Inorg Biochem 2009; 103:1426-38. [PMID: 19766319 DOI: 10.1016/j.jinorgbio.2009.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 06/05/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
Abstract
The stoichiometries and stability constants of a series of Al(3+)-N-phosponomethyl glycine (PMG/H(3)L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative (27)Al and (31)P NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6M NaCl, 25 degrees C). Besides the mononuclear AlH(2)L(2+), Al(H(2)L)(HL), Al(HL)(2)(-) and Al(HL)L(2-), dimeric Al(2)(HL)L(+) and trinuclear Al(3)H(5)L(4)(2+) complexes have been postulated. (1)H and (31)P NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the (31)P NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions.
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Affiliation(s)
- Mihály Purgel
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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28
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Bányai I, Conte V, Pettersson L, Silvagni A. On the Nature of VVSpecies in Hydrophilic Ionic Liquids: A Spectroscopic Approach. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Kálmán FK, Baranyai Z, Tóth I, Bányai I, Király R, Brücher E, Aime S, Sun X, Sherry AD, Kovács Z. Synthesis, potentiometric, kinetic, and NMR Studies of 1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)-4,10-bis(methylenephosphonic acid) (DO2A2P) and its complexes with Ca(II), Cu(II), Zn(II) and lanthanide(III) ions. Inorg Chem 2008; 47:3851-62. [PMID: 18380456 DOI: 10.1021/ic7024704] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A cyclen-based ligand containing trans-acetate and trans-methylenephosphonate pendant groups, H 6DO2A2P, was synthesized and its protonation constants (12.6, 11.43, 5.95, 6.15, 2.88, and 2.77) were determined by pH-potentiometry and (1)H NMR spectroscopy. The first two protonations were shown to occur at the two macrocyclic ring N-CH 2-PO 3 (2-) nitrogens while the third and fourth protonations occur at the two phosphonate groups. In parallel with protonation of the two -PO 3 (2-) groups, the protons from the NH (+)-CH 2-PO 3 (2-) are transferred to the N-CH 2-COO (-) nitrogens. The stability constants of the Ca (2+), Cu (2+), and Zn (2+) (ML, MHL, MH 2L, and M 2L) complexes were determined by direct pH-potentiometry. Lanthanide(III) ions (Ln (3+)) form similar species, but the formation of complexes is slow; so, "out-of-cell" pH-potentiometry (La (3+), Eu (3+), Gd (3+), Y (3+)) and competitive spectrophotometry with Cu(II) ion (Lu (3+)) were used to determine the stability constants. By comparing the log K ML values with those of the corresponding DOTA (H 4DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and DOTP (H 8DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid) complexes, the order DOTA < DO2A2P < DOTP was found for all the metal ion complexes examined here with the exception of the Ca (2+) complexes, for which the order is reversed. The relaxivity of Gd(DO2A2P) decreases between pH 2 and 7 but remains constant in the pH range of 7 < pH < 12 ( r 1 = 3.6 mM (-1) s (-1)). The linewiths of the (17)O NMR signals of water in the absence and presence of Gd(DO2A2P) (at pH = 3.45 and 8.5) between 274 and 350 K are practically the same, characteristic of a q = 0 complex. Detailed kinetic studies of the Ce (3+) and Gd (3+) complexes with DO2A2P showed that complex formation is slow and involves a high stability diprotonated intermediate Ln(H 2DO2A2P)*. Rearrangement of the diprotonated intermediate into the final complex is an OH (-) assisted process but, unlike formation of Ln(DOTA) complexes, rearrangement of Ln(H 2DO2A2P)* also takes place spontaneously likely as a result of transfer of one of the protons from a ring nitrogen to a phosphonate group. The order of the OH (-) assisted formation rates of complexes is DOTA > DO2A2P > DOTP while the order of the proton assisted dissociation rates of the Gd (3+) complexes is reversed, DOTP > DO2A2P > DOTA. (1)H and (13)C NMR spectra of Eu(DO2A2P) and Lu(DO2A2P) were assigned using two-dimensional correlation spectroscopy (2D COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear chemical shift correlation (HETCOR), and exchange spectroscopy (EXSY) NMR methods. Two sets of (1)H NMR signals were observed for Eu(DO2A2P) characteristic of the presence of two coordination isomers in solution, a twisted square antiprism (TSAP) and a square antiprism (SAP), in the ratio of ~93% and ~7%, respectively. Line shape analysis of the (1)H NMR spectra of Lu(DO2A2P) gave lower activation parameters compared to La(DOTP) for interconversion between coordination isomers. This indicates that the Ln(DO2A2P) complexes are less rigid probably due to the different size and spatial requirements of the carboxylate and phosphonate groups.
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Affiliation(s)
- Ferenc K Kálmán
- Department of Inorganic and Analytical Chemistry and Department of Colloid and Environmental Chemistry, University of Debrecen, Egyetem tér 1, Debrecen H-4010, Hungary
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30
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31
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Affiliation(s)
- István Bányai
- a Department of Physical Chemistry , Lajos Kossuth University , H-4010 , Debrecen , HungaryPf. 7
| | - László Dózsa
- a Department of Physical Chemistry , Lajos Kossuth University , H-4010 , Debrecen , HungaryPf. 7
| | - Mihály T. Beck
- a Department of Physical Chemistry , Lajos Kossuth University , H-4010 , Debrecen , HungaryPf. 7
| | - Gyöngyi Gyémánt
- b Department of Biochemistry , Lajos Kossuth University , H-4010 , Debrecen , Hungary
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Shi X, Bányai I, Rodriguez K, Islam MT, Lesniak W, Balogh P, Balogh LP, Baker JR. Electrophoretic mobility and molecular distribution studies of poly(amidoamine) dendrimers of defined charges. Electrophoresis 2006; 27:1758-67. [PMID: 16586414 DOI: 10.1002/elps.200500818] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Generation 5 ethylenediamine (EDA)-cored poly(amidoamine) (PAMAM) dendrimers (E5, E denotes the EDA core and 5 the generation number) with different degrees of acetylation and carboxylation were synthesized and used as a model system to investigate the effect of charge and the influence of dendrimer surface modifications on electrophoretic mobility (EM) and molecular distribution. The surface-modified dendrimers were characterized by size-exclusion chromatography, 1H NMR, MALDI-TOF-MS, PAGE, and CE. The focus of our study was to determine how EM changes as a function of particle charge and molecular mass, and how the molecular distribution changes due to surface modifications. We demonstrate that partially modified dendrimers have much broader migration peaks than those of fully surface functionalized or unmodified E5 dendrimers due to variations in the substitution of individual dendrimer surfaces. EM decreased nonlinearly with increases in surface acetylation for both PAMAM acetamides and PAMAM succinamic acids, indicating a complex migration activity in CE separations that is not solely due to charge/mass ratio changes. These studies provide new insights into dendrimer properties under an electric field, as well as into the characterization of dendrimer-based materials being developed for medical applications.
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Affiliation(s)
- Xiangyang Shi
- Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
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Jászberényi Z, Bányai I, Brücher E, Király R, Hideg K, Kálai T. Equilibrium and NMR studies on GdIII, YIII, CuIIand ZnIIcomplexes of various DTPA–N,N″-bis(amide) ligands. Kinetic stabilities of the gadolinium(iii) complexes. Dalton Trans 2006:1082-91. [PMID: 16474894 DOI: 10.1039/b514173g] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three DTPA-derivative ligands, the non-substituted DTPA-bis(amide) (L(0)), the mono-substituted DTPA-bis(n-butylamide) (L(1)) and the di-substituted DTPA-bis[bis(n-butylamide)] (L(2)) were synthesized. The stability constants of their Gd3+ complexes (GdL) have been determined by pH-potentiometry with the use of EDTA or DTPA as competing ligands. The endogenous Cu2+ and Zn2+ ions form ML, MHL and M(2)L species. For the complexes CuL(0) and CuL(1) the dissociation of the amide hydrogens (CuLH(-1)) has also been detected. The stability constants of complexes formed with Gd3+, Cu2+ and Zn2+ increase with an increase in the number of butyl substituents in the order ML(0) < ML(1) < ML(2). NMR studies of the diamagnetic YL(0) show the presence of four diastereomers formed by changing the chirality of the terminal nitrogens of their enantiomers. At 323 K, the enantiomerization process, involving the racemization of central nitrogen, falls into the fast exchange range. By the assignment and interpretation of 1H and 13C NMR spectra, the fractions of the diastereomers were found to be equal at pH = 5.8 for YL(0). The kinetic stabilities of GdL(0), GdL(1) and GdL(2) have been characterized by the rates of the exchange reactions occurring between the complexes and Eu3+, Cu2+ or Zn2+. The rates of reaction with Eu3+ are independent of the [Eu3+] and increase with increasing [H+], indicating the rate determining role of the proton assisted dissociation of complexes. The rates of reaction with Cu2+ and Zn2+ increase with rising metal ion concentration, which shows that the exchange can take place with direct attack of Cu2+ or Zn2+ on the complex, via the formation of a dinuclear intermediate. The rates of the proton, Cu2+ and Zn2+ assisted dissociation of Gd3+ complexes decrease with increasing number of the n-butyl substituents, which is presumably the result of steric hindrance hampering the formation or dissociation of the intermediates. The kinetic stabilities of GdL(0) and GdL(1) at pH = 7.4, [Cu2+] = 1 x 10(-6) M and [Zn(2+)] = 1 x 10(-5) M are similar to that of Gd(DTPA)2-, while the complex GdL2 possesses a much higher kinetic stability.
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Affiliation(s)
- Zoltán Jászberényi
- University of Debrecen, Department of Inorganic and Analytical Chemistry, H-4010, Debrecen, Hungary
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Csajbók E, Bányai I, Vander Elst L, Muller RN, Zhou W, Peters JA. Gadolinium(III)-Loaded Nanoparticulate Zeolites as Potential High-Field MRI Contrast Agents: Relationship Between Structure and Relaxivity. Chemistry 2005; 11:4799-807. [PMID: 15929138 DOI: 10.1002/chem.200500039] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of dealumination, pore size, and calcination on the efficiency (as expressed in the relaxivity) of Gd3+-loaded zeolites for potential application as magnetic resonance imaging (MRI) contrast agents were studied. Partial dealumination of zeolites NaY or NaA by treatment with (NH4)2SiF6 or diluted HCl resulted in materials that, upon loading with Gd3+, had a much higher relaxivity than the corresponding non-dealuminated materials. Analysis of the 1H NMR dispersion profiles of the various zeolites showed that this can be mainly ascribed to an increase of the amount of water inside the zeolite cavities as a result of the destruction of walls between cavities. However, the average residence time of water inside the Gd3+-loaded cavities did not change significantly, which suggests that the windows of the Gd3+-loaded cavities are not affected by the dealumination. Upon calcination, the Gd3+ ions moved to the small sodalite cavities and became less accessible for water, resulting in a decrease in relaxivity. The important role of diffusion for the relaxivity was demonstrated by a comparison of the relaxivity of Gd3+-loaded zeolite NaY and NaA samples. NaA had much lower relaxivities due to the smaller pore sizes. The transversal relaxivities of the Gd3+-doped zeolites are comparable in magnitude to the longitudinal ones at low magnetic fields (<60 MHz). However at higher fields, the transversal relaxivities steeply increased, whereas the longitudinal relaxivities decreased as field strength increased. Therefore, these materials have potential as T1 MRI contrast agents at low field, and as T2 agents at higher fields.
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Affiliation(s)
- Eva Csajbók
- Laboratory of Applied Organic Chemistry and Catalysis, Delft University of Technology, The Netherlands
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Shi X, Bányai I, Lesniak WG, Islam MT, Országh I, Balogh P, Baker JR, Balogh LP. Capillary electrophoresis of polycationic poly(amidoamine) dendrimers. Electrophoresis 2005; 26:2949-59. [PMID: 15995982 DOI: 10.1002/elps.200500134] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Generation 2 to generation 5 poly(amidoamine) (PAMAM) dendrimers having different terminal functionalities were analyzed by capillary electrophoresis (CE). Polyacrylamide gel electrophoresis was also used to assess the composition of the individual generations for comparison with the CE results. Separation of PAMAMs can be accomplished by either using uncoated silica or silanized silica capillaries, although reproducibility is poor using the uncoated silica capillary. To improve run-to-run reproducibility, silanized capillary was used and various internal standards were also tested. Relative and normalized migration times of primary amine terminated PAMAM dendrimers were then determined using 2,3-diaminopyridine (2,3-DAP) as an internal standard. Using silanized capillaries and internal standards, the relative and normalized migration times are fully reproducible and comparable between runs. Apparent dimensionless electrophoretic mobilities were determined and the results were compared to theoretical calculations. It is concluded that for PAMAMs a complex separation mechanism has to be considered in CE, where the movement of the ions is due to the electric field, but the separation is rather the consequence of the adsorption/desorption equilibria on the capillary wall ("electrokinetic capillary chromatography"). The described method may be used for quality control and may serve as an effective technique to analyze polycationic PAMAM dendrimers and their derivatives with different surface modifications.
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Affiliation(s)
- Xiangyang Shi
- Center for Biologic Nanotechnology, University of Michigan Medical School, Ann Arbor, USA
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Abstract
Slowly diffusing water molecules were found by quasi-elastic neutron scattering (QENS) in a sodium dodecyl sulfate (SDS) micellar solution, and both their diffusion coefficient (4.33 x 10(-6) cm2 x s(-1)) and mole fraction (0.057) were determined. After successfully checking the mean slowing down of solvent molecules by the gradient compensated stimulated spin-echo (GCSTE) pulse sequence NMR method, a similar effect was observed with this technique in the solvent phase of dodecyl trimethylammonium bromide (DTAB) and differing chain length (X = 12, 20, 30, and 40) ethoxylated nonyl phenol (9NX) micellar systems. Following the literature, the experimental results are qualitatively explained by assuming that, apart from ionic hydration, H-bonds may form between the solvent molecules and the O or N atoms present in the hydrophilic (head)groups of the micelle-forming monomers.
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Csajbók E, Bányai I, Brücher E. Dynamic NMR properties of DOTA ligand: variable pH and temperature1H NMR study on [K(HxDOTA)](3−x)−species. Dalton Trans 2004:2152-6. [PMID: 15249951 DOI: 10.1039/b405116e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The (1)H NMR spectra of [H(x)DOTA]((4-x)-) species are reported as a function of pH and temperature in aqueous solution. The spectra show line broadening both in ligand proton signals and also in the water proton signal by titration with KOH solution. The formation of different [K(H(x)DOTA)]((3-x)-) complexes is found to be responsible for this behaviour. At high pH the usual fluxional motions, i.e. the ring inversion and the change in the acetate arms' helicity, which are also characteristic for other but inert metal-DOTA complexes, have been detected. However, because of the kinetic lability of K(+)-O and K(+)-N coordinative bonds a new type of rearrangement appears. This new motion requires breaking of coordinative bonds in the complex and can be described as a certain type of "ring slewing" around the ring C-C bonds. At low temperature (about 270 K) the ring slewing slows down and becomes negligible compared with the ring inversion and the change in the arms' helicity. These two latter processes have the same rate. When the temperature is higher (about 320 K) the ring slewing accelerates and its rate exceeds the rate of ring inversion. At this temperature the change in the acetate arms' helicity has the same rate as the ring slewing. Additionally, in the pH range 4-5 a slow intermolecular proton exchange process has been observed between the water and the dissociable protons of [K(H(x)DOTA)]((3-x)-). A water-assisted proton exchange mechanism is proposed on the basis of the activation parameters. This finding supports the previously suggested slow proton motion hypothesis for the formation of DOTA complexes.
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Affiliation(s)
- Eva Csajbók
- Department of Physical Chemistry, University of Debrecen, H-4010 Debrecen, Pf.7., Hungary.
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Fekete E, Karaffa L, Sándor E, Bányai I, Seiboth B, Gyémánt G, Sepsi A, Szentirmai A, Kubicek CP. The alternative D-galactose degrading pathway of Aspergillus nidulans proceeds via L-sorbose. Arch Microbiol 2003; 181:35-44. [PMID: 14624333 DOI: 10.1007/s00203-003-0622-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2003] [Revised: 10/14/2003] [Accepted: 10/17/2003] [Indexed: 11/29/2022]
Abstract
The catabolism of d-galactose in yeast depends on the enzymes of the Leloir pathway. In contrast, Aspergillus nidulans mutants in galactokinase ( galE) can still grow on d-galactose in the presence of ammonium-but not nitrate-ions as nitrogen source. A. nidulans galE mutants transiently accumulate high (400 mM) intracellular concentrations of galactitol, indicating that the alternative d-galactose degrading pathway may proceed via this intermediate. The enzyme degrading galactitol was identified as l-arabitol dehydrogenase, because an A. nidulans loss-of-function mutant in this enzyme ( araA1) did not show NAD(+)-dependent galactitol dehydrogenase activity, still accumulated galactitol but was unable to catabolize it thereafter, and a double galE/araA1 mutant was unable to grow on d-galactose or galactitol. The product of galactitol oxidation was identified as l-sorbose, which is a substrate for hexokinase, as evidenced by a loss of l-sorbose phosphorylating activity in an A. nidulans hexokinase ( frA1) mutant. l-Sorbose catabolism involves a hexokinase step, indicated by the inability of the frA1 mutant to grow on galactitol or l-sorbose, and by the fact that a galE/frA1 double mutant of A. nidulans was unable to grow on d-galactose. The results therefore provide evidence for an alternative pathway of d-galactose catabolism in A. nidulans that involves reduction of the d-galactose to galactitol and NAD(+)-dependent oxidation of galactitol by l-arabitol dehydrogenase to l-sorbose.
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Affiliation(s)
- Erzsébet Fekete
- Department of Microbiology and Biotechnology, University of Debrecen, Faculty of Sciences, P.O.Box 63, 4010 Debrecen, Hungary
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Abstract
The first conformer-specific experimental partition coefficients are presented for octanol/water, the most widespread solvent system to predict lipophilicity of drugs. Rotamer populations in octanol and water were elucidated from 1H NMR vicinal coupling constants and were combined with classical partition coefficients to obtain the conformer-specific ones. Feasibility of the determination of conformer-specific partition coefficients is exemplified on amphetamine and clenbuterol, two flexible drug molecules. Partition capacities of the amphetamine rotamers have been proven to be essentially equal. The conformers of clenbuterol, however, have been found to be greatly different in partition properties, which could be interpreted in terms of intramolecular interactions between the vicinal polar sites and the solvent-accessibility of the groups. The conformers could be put into order of their membrane-influx and -outflow propensities. Deviations between experimental and calculated log P values could also be interpreted in view of the species-specific partition coefficients.
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Affiliation(s)
- Márta Kraszni
- Semmelweis University, Department of Pharmaceutical Chemistry, H-1092 Budapest, Högyes E. u. 9., Hungary
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Csajbók E, Baranyai Z, Bányai I, Brücher E, Király R, Müller-Fahrnow A, Platzek J, Radüchel B, Schäfer M. Equilibrium, 1H and 13C NMR spectroscopy, and X-ray diffraction studies on the complexes Bi(DOTA)- and Bi(DO3A-Bu). Inorg Chem 2003; 42:2342-9. [PMID: 12665368 DOI: 10.1021/ic0261272] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several Bi(III) complexes are used in medicine as drugs. Bi(DO3A-Bu) has recently been proposed as a nonionic contrast agent in X-ray imaging (H(3)DO3A-Bu = 10-[2,3-dihydroxy-(1-hydroxymethyl)propyl]-1,4,7,10-tetraazacyclododecane-1,4,7,-triacetic acid). The solution equilibria and NMR structure and dynamics of Bi(DO3A-Bu) and of the similar Bi(DOTA)(-) have been investigated (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). The stability constants were determined with the study of the competition equilibria between Br(-) ions and the ligands DOTA or DO3A-Bu for the Bi(III) by spectrophotometry. The stability constants, obtained for Bi(DOTA)(-) and Bi(DO3A-Bu), are very high, log K = 30.3 and 26.8, respectively. Potentiometric titrations indicated the dissociation of one of the protons among the three alcoholic OH groups in Bi(DO3A-Bu). The dissociation constant is log K = 7.53 (0.09) indicating that at physiological pH about 50% of the species possess -1 charge. It was shown by (1)H and (13)C NMR spectroscopy that the OH group attached to the middle carbon atom of the "butriol" side chain is coordinated to the Bi(III) and starts to deprotonate at pH > 5.5. The crystal structure of NaBi(DOTA).H(2)O shows an octacoordinated arrangement of the donor atoms around the Bi(III), with no water in the inner sphere. The crystals belong to the centrosymmetric space group C2/c. The temperature dependent (1)H and (13)C NMR spectra indicate that both Bi(DOTA)(-) and Bi(DO3A-Bu)(-) complexes are fluxional. For Bi(DOTA), the Delta(deltadeltadeltadelta) right harpoon over left harpoon Lambda(lambdalambdalambdalambda) fluxionality was identified, and on the basis of the activation parameters, a synchronous motion was suggested for the fluxional motion resulting in the change of ring conformation and of the helicity of the complex. The transition state is supposed to be more symmetrical than the initial state. The deprotonated Bi(DO3A-Bu) has a highly asymmetric NMR structure in solution, and its fluxional motion is slower than that of Bi(DOTA)(-).
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Affiliation(s)
- Eva Csajbók
- Department of Physical Chemistry, University of Debrecen, H-4010, Debrecen, Hungary
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Ambrus A, Bányai I, Weiss MS, Hilgenfeld R, Keresztessy Z, Muszbek L, Fésüs L. Calcium binding of transglutaminases: a 43Ca NMR study combined with surface polarity analysis. J Biomol Struct Dyn 2001; 19:59-74. [PMID: 11565852 DOI: 10.1080/07391102.2001.10506720] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Transglutaminases (TGases) form cross-links between glutamine and lysine side-chains of polypeptides in a Ca2+-dependent reaction. The structural basis of the Ca2+-effect is poorly defined. 43Ca NMR, surface polarity analysis combined with multiple sequence alignment and the construction of a new homology model of human tissue transglutaminase (tTGase) were used to obtain structural information about Ca2+ binding properties of factor XIII-A2, tTGase and TGase 3 (each of human origin). 43Ca NMR provided higher average dissociation constants titrating on a wide Ca2+-concentration scale than previous studies with equilibrium dialysis performed in shorter ranges. These results suggest the existence of low affinity Ca2+ binding sites on both FXIII-A and tTGase in addition to high affinity ones in accordance with our surface polarity analysis identifying high numbers of negatively charged clusters. Upon increasing the salt concentration or activating with thrombin, FXIII-A2 partially lost its original Ca2+ affinity; the NMR data suggested different mechanisms for the two activation processes. The NMR provided structural evidence of GTP-induced conformational changes on the tTGase molecule diminishing all of its Ca2+ binding sites. NMR data on the Ca2+ binding properties of the TGase 3 are presented here; it binds Ca2+ the most tightly, which is weakened after its proteolytic activation. The investigated TGases seem to have very symmetric Ca2+ binding sites and no EF-hand motifs.
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Affiliation(s)
- A Ambrus
- University of Debrecen, Department of Biochemistry and Molecular Biology, Hungary
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Berka M, Bányai I. Surface Complexation Modeling of K(+), NO(3)(-), SO(4)(2-), Ca(2+), F(-), Co(2+), and Cr(3+) Ion Adsorption on Silica Gel. J Colloid Interface Sci 2001; 233:131-135. [PMID: 11112316 DOI: 10.1006/jcis.2000.7233] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Surface complex formation of K(+), NO(3)(-), SO(4)(2-), Ca(2+), F(-), Co(2+), and Cr(3+) ions was determined on the surface of silica gel. Experimental data obtained by acid-base titration of suspensions were interpreted in terms of the triple-layer model. The value of the deprotonation constant of surface OH could be determined precisely but the protonation constant was rather uncertain. The logarithms of ion pair formation constants for K(+), NO(3)(-), Ca(2+), and SO(4)(2-) adsorbed in the beta-plane are log K(ipM,X) approximately 0, therefore these species can be considered inert ions in the investigated pH range. F(-), Co(2+), and Cr(3+) ions were found to be strongly sorbed in the o-plane. In order to provide a good fit and to obtain parameters independent of their initial values, all possible equilibrium must be accounted for in the models. Copyright 2001 Academic Press.
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Affiliation(s)
- M Berka
- Department of Colloid Chemistry, University of Debrecen, Debrecen, Debrecen, 4010, Hungary
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Abstract
A careful reinvestigation by high-field 19F NMR (470 MHz) spectroscopy has been made of the Al3+/F- system in aqueous solution under carefully controlled conditions of pH, concentration, ionic strength (I), and temperature. The 19F NMR spectra show five distinct signals at 278 K and I = 0.6 M (TMACl) which have been attributed to the complexes AlFi(3-i)+(aq) with i < or = 5. There was no need to invoke AlFi(OH)j(3-i-j)+ mixed complexes in the model under our experimental conditions (pH < or = 6.5), nor was any evidence obtained for the formation of AlF6(3-)(aq) at very high ratios of F-/Al3+. The stepwise equilibrium constants obtained for the complexes by integration of the 19F signals are in good agreement with literature data given the differences in medium and temperature. In I = 0.6 M TMACl at 278 K and in I = 3 M KCl at 298 K the log Ki values are 6.42, 5.41, 3.99, 2.50, and 0.84 (for species i = 1-5) and 6.35, 5.25, and 4.11 (for species i = 1-3), respectively. Disappearance of the 19F NMR signals under certain conditions was shown to be due to precipitation. Certain 19F NMR signals exhibit temperature- and concentration-dependent exchange broadening. Detailed line shape analysis of the spectra and magnetization transfer measurements indicate that the kinetics are dominated by F- exchange rather than complex formation. The detected reactions and their rate constants are AlF2(2+) + *F- reversible AlF*F2+ + F- (k02 = (1.8 +/- 0.3) x 10(6) M-1 s-1), AlF3(0) + *F- reversible AlF2*F0 + F- (k03 = (3.9 +/- 0.9) x 10(6) M-1 s-1), and AlF3(0) + H*F reversible AlF2*F0 + HF (kH03 = (6.6 +/- 0.5) x 10(4) M-1 s-1). The rates of these exchange reactions increase markedly with increasing F- substitution. Thus, the reactions of AlF2+(aq) were too inert to be detected even on the T1 NMR time scale, while some of the reactions of AlF3(0)(aq) were fast, causing large line broadening. The ligand exchange appears to follow an associative interchange mechanism. The cis-trans isomerization of AlF2+(aq), consistent with octahedral geometry for that complex, is slowed sufficiently to be observed at temperatures around 270 K. Difference between the Al3+/F- system and the much studied Al3+/OH- system are briefly commented on.
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Affiliation(s)
- A Bodor
- Department of Inorganic and Analytical Chemistry, Lajos Kossuth University (KLTE), H-4010 Debrecen, Pf. 21, Hungary
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Farkas I, Bányai I, Szabó Z, Wahlgren U, Grenthe I. Rates and mechanisms of water exchange of UO2(2+)(aq) and UO2(oxalate)F(H2O)2-: a variable-temperature 17O and 19F NMR study. Inorg Chem 2000; 39:799-805. [PMID: 11272579 DOI: 10.1021/ic990929o] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study consists of two parts: The first part comprised an experimental determination of the kinetic parameters for the exchange of water between UO2(H2O)5(2+) and bulk water, including an ab initio study at the SCF and MP2 levels of the geometry of UO2(H2O)5(2+), UO2(H2O)4(2+), and UO2(H2O)6(2+) and the thermodynamics of their reactions with water. In the second part we made an experimental study of the rate of water exchange in uranyl complexes and investigated how this might depend on inter- and intramolecular hydrogen bond interactions. The experimental studies, made by using 17O NMR, with Tb3+ as a chemical shift reagent, gave the following kinetic parameters at 25 degrees C: kex = (1.30 +/- 0.05) x 10(6) s(-1); deltaH(not equal to) = 26.1 +/- 1.4 kJ/mol; deltaS(not equal to) = -40 +/- 5J J/(K mol). Additional mechanistic indicators were obtained from the known coordination geometry of U(VI) complexes with unidentate ligands and from the theoretical calculations. A survey of the literature shows that there are no known isolated complexes of UO2(2+) with unidentate ligands which have a coordination number larger than 5. This was corroborated by quantum chemical calculations which showed that the energy gains by binding an additional water to UO2(H2O)4(2+) and UO2(H2O)5(2+) are 29.8 and -2.4 kcal/mol, respectively. A comparison of the change in deltaU for the reactions UO2(H2O)5(2+)--> UO2(H2O)4(2+) + H2O and UO2(H2O)5(2+) + H2O --> UO2(H2O)6(2+) indicates that the thermodynamics favors the second (associative) reaction in gas phase at 0 K, while the thermodynamics of water transfer between the first and second coordination spheres, UO2(H2O)5(2+) --> UO2(H2O)4(H2O)2+ and UO2(H2O)5(H2O)2+ --> UO2(H2O)6(2+), favors the first (dissociative) reaction. The energy difference between the associative and dissociative reactions is small, and solvation has to be included in ab initio models in order to allow quantitative comparisons between experimental data and theory. Theoretical calculations of the activation energy were not possible because of the excessive computing time required. On the basis of theoretical and experimental studies, we suggest that the water exchange in UO2(H2O)5(2+) follows a dissociative interchange mechanism. The rates of exchange of water in UO2(oxalate)F(H2O)2- (and UO2(oxalate)F2(H2O)2- studied previously) are much slower than in the aqua ion, kex = 1.6 x 10(4) s(-1), an effect which we assign to hydrogen bonding involving coordinated water and fluoride. The kinetic parameters for the exchange of water in UO2(H2O)52+ and quenching of photo excited *UO2(H2O)5(2+) are very near the same, indicating similar mechanisms.
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Affiliation(s)
- I Farkas
- Department of Chemistry, Inorganic Chemistry, The Royal Institute of Technology (KTH), Stockholm, Sweden
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Farkas I, Grenthe I, Bányai I. The Rates and Mechanisms of Water Exchange of Actinide Aqua Ions: A Variable Temperature 17O NMR Study of U(H2O)104+, UF(H2O)93+, and Th(H2O)104+. J Phys Chem A 2000. [DOI: 10.1021/jp992934j] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ildikó Farkas
- Department of Chemistry, Inorganic Chemistry, The Royal Institute of Technology (KTH), Stockholm, Sweden
| | - Ingmar Grenthe
- Department of Chemistry, Inorganic Chemistry, The Royal Institute of Technology (KTH), Stockholm, Sweden
| | - István Bányai
- Department of Physical Chemistry, Lajos Kossuth University, Debrecen, Hungary
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Sarka L, Bányai I, Brücher E, Király R, Platzek J, Radüchel B, Schmitt‐Willich H. Synthesis, equilibrium and NMR studies of lanthanide(III) complexes of the N-mono(methylamide) and N ′-mono(methylamide) derivatives of diethylenetriamine-N,N,N ′,N ″,N ″-pentaacetic acid†. ACTA ACUST UNITED AC 2000. [DOI: 10.1039/b005298l] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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