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Bondžić AM, Vasić Anićijević DD, Janjić GV, Zeković I, Momić T, Nikezić AV, Vasić VM. Na, K-ATPase as a Biological Target for Gold(III) Complexes: A Theoretical and Experimental Approach. Curr Med Chem 2021; 28:4742-4798. [PMID: 33397227 DOI: 10.2174/0929867328999210101233801] [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] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Gold-based complexes represent a new class of potential metallodrugs. Although their action mechanism is not entirely understood, it was shown that gold complexes inhibit some enzymes' activities. Among them, Na,K-ATPase is emerging as an essential target for various anticancer drugs. The functionalization of nanoparticles by gold(III) complexes could facilitate their delivery into the cells and enable the following of their distribution in the target tissues. OBJECTIVE The paper presents an overview of Na,K-ATPase interaction with representative and structurally related cytotoxic gold(III) complexes. The results obtained by the employment of theoretical methods (DFT and docking studies) combined with the experimental approach involving a variety of nanotechnology-base techniques (UV/Vis, Raman and fluorescence spectroscopy, CD, AFM, DLS) are discussed. Detailed information was obtained on the enzyme's conformational and structural changes upon binding the gold(III) complexes. The experimentally determined reaction parameters (constants of dissociation and the reaction stoichiometry) were predicted theoretically. CONCLUSION The presented results offer further support to the view that Na,K-ATPase may be a relevant biomolecular target for cytotoxic gold(III) compounds of medicinal interest.
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Affiliation(s)
- Aleksandra M Bondžić
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
| | - Dragana D Vasić Anićijević
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
| | - Goran V Janjić
- Institute of Chemistry, Technology and Metallurgy, National Institute of thе Republic of Serbia, University of Belgrade, Njegoseva 16, Belgrade, Serbia
| | - Ivana Zeković
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
| | - Tatjana Momić
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
| | - Ana Vujačić Nikezić
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
| | - Vesna M Vasić
- VINCA Institute of Nuclear Sciences, National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, 11000 Belgrade, Serbia
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Veljović DN, Gurešić DM, Jokić AB, Vasić VM, Laban BB. Solid‐State Synthesis of Silver Nanoparticles and Their Catalytic Application in Methylene Blue Reduction. ChemistrySelect 2020. [DOI: 10.1002/slct.202001829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Djordje N. Veljović
- Faculty of Technology and Metallurgy University of Belgrade Karnegijeva 4 11000 Belgrade Serbia
| | - Dejan M. Gurešić
- Faculty of Technical Sciences University of Priština, Knjaza Miloša 7 38220 Kosovska Mitrovica Serbia
| | - Anja B. Jokić
- Faculty of Sciences, University of Priština-Kosovska Mitrovica Department of Chemistry, 38220 Kosovska Mitrovica, Serbia Lole Ribara 29 38220 Kosovska Mitrovica Serbia
| | - Vesna M. Vasić
- Vinča Institute of Nuclear Sciences University of Belgrade P.O. Box 522 Belgrade Serbia
| | - Bojana B. Laban
- Faculty of Sciences, University of Priština-Kosovska Mitrovica Department of Chemistry, 38220 Kosovska Mitrovica, Serbia Lole Ribara 29 38220 Kosovska Mitrovica Serbia
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Savić JZ, Petrović SŽ, Leskovac AR, Lazarević Pašti TD, Nastasijević BJ, Tanović BB, Gašić SM, Vasić VM. UV-C light irradiation enhances toxic effects of chlorpyrifos and its formulations. Food Chem 2019; 271:469-478. [DOI: 10.1016/j.foodchem.2018.07.207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 04/10/2018] [Accepted: 07/29/2018] [Indexed: 10/28/2022]
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Vujačić Nikezić AV, Janjić GV, BondŽić AM, Zarić BL, Vasić-Anićijević DD, Momić TG, Vasić VM. Interaction of Au(iii) and Pt(ii) complexes with Na/K-ATPase: experimental and theoretical study of reaction stoichiometry and binding sites. Metallomics 2018; 10:1003-1015. [PMID: 29978878 DOI: 10.1039/c8mt00111a] [Citation(s) in RCA: 2] [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: 12/23/2022]
Abstract
The present paper deals with investigation of the interaction between selected simple structure Au(iii) ([AuCl4]-, [AuCl2(dmso)2]+, [AuCl2(bipy)]+) and Pt(ii) ([PtCl2(dmso)2]) complexes with Na/K-ATPase as the target enzyme, using an experimental and theoretical approach. Reaction stoichiometries and binding constants for these enzyme/complex systems were determined, while kinetic measurements were used in order to reveal the type of inhibition. Based on the results obtained by quantum mechanical calculations (electrostatic surface potential (ESP), volume and surface of the complexes) the nature of the investigated complexes was characterized. By using the solvent accessible surface area (SASA) applied on specific inhibitory sites (ion channel and intracellular domains) the nature of these sites was described. Docking studies were used to determine the theoretical probability of the non-covalent metal binding site positions. Inhibition studies implied that all the investigated complexes decreased the activity of the enzyme while the kinetic analysis indicated an uncompetitive mode of inhibition for the selected complexes. Docking results suggested that the main inhibitory site of all these complexes is located in the ion translocation pathway on the extracellular side in the E2P enzyme conformation, similar to the case of cardiac glycosides, specific Na/K-ATPase inhibitors. Also, based on our knowledge, the hydrolyzed forms of [AuCl4]- and [PtCl2(dmso)2] complexes were investigated for the first time by theoretical calculations in this paper. Thereby, a new inhibitory site situated between the M2 and M4 helices was revealed. Binding in this site induces conformational changes in the enzyme domains and perturbs the E1-E2P conformational equilibrium, causing enzyme inhibition.
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Bondžić AM, Janjić GV, Dramićanin MD, Messori L, Massai L, Parac Vogt TN, Vasić VM. Na/K-ATPase as a target for anticancer metal based drugs: insights into molecular interactions with selected gold(iii) complexes. Metallomics 2017; 9:292-300. [PMID: 28181616 DOI: 10.1039/c7mt00017k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Na/K-ATPase is emerging as an important target for a variety of anticancer metal-based drugs. The interactions of Na/K-ATPase (in its E1 state) with three representative and structurally related cytotoxic gold(iii) complexes, i.e. [Au(bipy)(OH)2][PF6], bipy = 2,2'-bipyridine; [Au(pydmb-H)(CH3COO)2], pydmb-H = deprotonated 6-(1,1-dimethylbenzyl)-pyridine and [Au(bipydmb-H)(OH)][PF6], bipyc-H = deprotonated 6-(1,1-dimethylbenzyl)-2,2'-bipyridine, are investigated here in depth using a variety of spectroscopic methods, in combination with docking studies. Detailed information is gained on the conformational and structural changes experienced by the enzyme upon binding of these gold(iii) complexes. The quenching constants of intrinsic enzyme fluorescence, the fraction of Trp residues accessible to gold(iii) complexes and the reaction stoichiometries were determined in various cases. Specific hypotheses are made concerning the binding mode of these gold(iii) complexes to the enzyme and the likely binding sites. Differences in their binding behaviour toward Na/K-ATPase are explained on the ground of their distinctive structural features. The present results offer further support to the view that Na/K-ATPase may be a relevant biomolecular target for cytotoxic gold(iii) compounds of medicinal interest and may thus be involved in their overall mode of action.
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Affiliation(s)
- Aleksandra M Bondžić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, Belgrade, 11000, Serbia.
| | - Goran V Janjić
- Institute of Chemistry, Metallurgy and Technology, University of Belgrade, Njegoseva Street 12, Belgrade, 11000, Serbia
| | - Miroslav D Dramićanin
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, Belgrade, 11000, Serbia.
| | - Luigi Messori
- Department of Chemistry, University of Florence, Via Della Lastruccia 3, Sesto Fiorentino, 50019, Italy.
| | - Lara Massai
- Department of Chemistry, University of Florence, Via Della Lastruccia 3, Sesto Fiorentino, 50019, Italy.
| | | | - Vesna M Vasić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 522, Belgrade, 11000, Serbia.
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Bondžić AM, Čolović MB, Janjić GV, Zarić B, Petrović S, Krstić DZ, Marzo T, Messori L, Vasić VM. The influence of oxo-bridged binuclear gold(III) complexes on Na/K-ATPase activity: a joint experimental and theoretical approach. J Biol Inorg Chem 2017; 22:819-832. [PMID: 28432453 DOI: 10.1007/s00775-017-1460-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/09/2017] [Indexed: 11/29/2022]
Abstract
The in vitro effects of oxo-bridged binuclear gold(III) complexes, i.e., [(bipy2Me)2Au2(μ-O)2][PF6]2 (Auoxo6), Au2[(bipydmb-H)2(μ-O)][PF6] (Au2bipyC) and [Au2(phen2Me)2(μ-O)2](PF6)2 (Au2phen) on Na/K-ATPase, purified from the porcine cerebral cortex, were investigated. All three studied gold complexes inhibited the enzyme activity in a concentration-dependent manner achieving IC50 values in the low micromolar range. Kinetic analysis suggested an uncompetitive mode of inhibition for Auoxo6 and Au2bipyC, and a mixed type one for Au2phen. Docking studies indicated that the inhibitory actions of all tested complexes are related to E2-P enzyme conformation binding to ion channel and intracellular part between N and P sub-domain. In addition, Au2phen was able to inhibit the enzyme by interacting with its extracellular part as well. Toxic effects of the gold(III) complexes were evaluated in vitro by following lactate dehydrogenase activity in rat brain synaptosomes and incidence of micronuclei and cytokinesis-block proliferation index in cultivated human lymphocytes. All investigated complexes turned out to induce cytogenetic damage consisting of a significant decrease in cell proliferation and an increase in micronuclei in a dose-dependent manner. On the other hand, lactate dehydrogenase activity, an indicator of membrane integrity/viability, was not affected by Auoxo6 and Au2bipyC, while Au2phen slightly modified its activity.
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Affiliation(s)
- Aleksandra M Bondžić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11 001, Belgrade, Serbia
| | - Mirjana B Čolović
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11 001, Belgrade, Serbia
| | - Goran V Janjić
- Institute of Chemistry, Metallurgy and Technology, University of Belgrade, Belgrade, Serbia
| | - Božidarka Zarić
- Institute of Chemistry, Metallurgy and Technology, University of Belgrade, Belgrade, Serbia
| | - Sandra Petrović
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11 001, Belgrade, Serbia
| | - Danijela Z Krstić
- Institute of Medical Chemistry, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia
| | - Tiziano Marzo
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.,Department of Chemistry and Industrial Chemistry, University of Pisa, Via Moruzzi 13, 56124, Pisa, Italy
| | - Luigi Messori
- Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Vesna M Vasić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11 001, Belgrade, Serbia.
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Xu X, Bošnjaković-Pavlović N, Čolović MB, Krstić DZ, Vasić VM, Gillet JM, Wu P, Wei Y, Spasojević-de Biré A. A combined crystallographic analysis and ab initio calculations to interpret the reactivity of functionalized hexavanadates and their inhibitor potency toward Na(+)/K(+)-ATPase. J Inorg Biochem 2016; 161:27-36. [PMID: 27235271 DOI: 10.1016/j.jinorgbio.2016.04.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 11/22/2015] [Revised: 04/16/2016] [Accepted: 04/25/2016] [Indexed: 02/02/2023]
Abstract
In vitro influence of five synthesized functionalized hexavanadates (V6) on commercial porcine cerebral cortex Na(+)/K(+)-ATPase activity has been studied. Dose dependent Na(+)/K(+)-ATPase inhibition was obtained for all investigated compounds. Calculated half maximal inhibitory concentration IC50 values, in mol/L, for Na(+)/K(+)-ATPase were 7.6×10(-5), 1.8×10(-5), 2.9×10(-5), 5.5×10(-5) for functionalized hexavanadates (V6) with tetrabutylammonium (TBA) [V6-CH3][TBA]2, [V6-NO2][TBA]2, [V6-OH][TBA]2 and [V6-C3][TBA]2 respectively. [V6-OH][Na]2 inhibited Na(+)/K(+)-ATPase activity up to 30% at maximal investigated concentration 1×10(-3)mol/L. This reactivity has been interpreted using a study of the non-covalent interactions of functionalized hexavanadate hybrids through Cambridge Structural Database (CSD) analysis. Bibliographic searching has led to 18 different structures and 99 contacts. We have observed that C-H⋯O contacts consolidate the structures. We have also performed density functional theory (DFT) calculations and have determined electrostatic potential values at the molecular surface on a series of functionalized V6. These results enlightened their chemical reactivity and their potential biological applications such as the inhibition of the ATPase.
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Affiliation(s)
- Xiao Xu
- Université Paris Saclay, CentraleSupélec, Campus de Châtenay, Grande Voie des Vignes, 92295 Châtenay-Malabry, France; CNRS, UMR 8580, Laboratory "Structures Propriétés et Modélisation des Solides" (SPMS), Grande Voie des Vignes, 92295 Châtenay-Malabry, France
| | | | - Mirjana B Čolović
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O.Box 522, Belgrade, Serbia
| | - Danijela Z Krstić
- University School of Medicine, Institute of Medical Chemistry, University of Belgrade, Višegradska 26, 11000 Belgrade, Serbia
| | - Vesna M Vasić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O.Box 522, Belgrade, Serbia
| | - Jean-Michel Gillet
- Université Paris Saclay, CentraleSupélec, Campus de Châtenay, Grande Voie des Vignes, 92295 Châtenay-Malabry, France; CNRS, UMR 8580, Laboratory "Structures Propriétés et Modélisation des Solides" (SPMS), Grande Voie des Vignes, 92295 Châtenay-Malabry, France
| | - Pingfan Wu
- Institute of POM-based Materials, The Synergistic Innovation Center of Catalysis Materials of Hubei Province, Hubei University of Technology, 430086 Wuhan, Hubei Province, P. R. China
| | - Yongge Wei
- Department of Chemistry, Tsinghua University, 100084 Beijing, P.R. China
| | - Anne Spasojević-de Biré
- Université Paris Saclay, CentraleSupélec, Campus de Châtenay, Grande Voie des Vignes, 92295 Châtenay-Malabry, France; CNRS, UMR 8580, Laboratory "Structures Propriétés et Modélisation des Solides" (SPMS), Grande Voie des Vignes, 92295 Châtenay-Malabry, France
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Lazarević-Pašti TD, Pašti IA, Jokić B, Babić BM, Vasić VM. Heteroatom-doped mesoporous carbons as efficient adsorbents for removal of dimethoate and omethoate from water. RSC Adv 2016. [DOI: 10.1039/c6ra06736k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [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
B-, N- and P-doped mesoporous carbons have been successfully applied for removal of dimethoate and omethoate from water.
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Affiliation(s)
| | - Igor A. Pašti
- University of Belgrade
- Faculty of Physical Chemistry
- 11158 Belgrade
- Serbia
| | - Bojan Jokić
- Faculty of Technology and Metallurgy
- University of Belgrade
- 11000 Belgrade
- Serbia
- Faculty of Applied Arts
| | - Biljana M. Babić
- Vinča Institute of Nuclear Sciences
- University of Belgrade
- 11001 Belgrade
- Serbia
| | - Vesna M. Vasić
- Vinča Institute of Nuclear Sciences
- University of Belgrade
- 11001 Belgrade
- Serbia
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Čolović MB, Krstić DZ, Lazarević-Pašti TD, Bondžić AM, Vasić VM. Acetylcholinesterase inhibitors: pharmacology and toxicology. Curr Neuropharmacol 2013; 11:315-35. [PMID: 24179466 PMCID: PMC3648782 DOI: 10.2174/1570159x11311030006] [Citation(s) in RCA: 1325] [Impact Index Per Article: 120.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 01/04/2013] [Accepted: 02/02/2013] [Indexed: 12/12/2022] Open
Abstract
Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimer's disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases.
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Affiliation(s)
- Mirjana B Čolović
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia
| | - Danijela Z Krstić
- University School of Medicine, Institute of Medical Chemistry, University of Belgrade, Belgrade, Serbia
| | - Tamara D Lazarević-Pašti
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia
| | - Aleksandra M Bondžić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia
| | - Vesna M Vasić
- Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia
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Lazarević-Pašti TD, Bondžić AM, Pašti IA, Mentus SV, Vasić VM. Electrochemical oxidation of diazinon in aqueous solutions via electrogenerated halogens – Diazinon fate and implications for its detection. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Bondžić AM, Lazarević-Pašti TD, Bondžić BP, Čolović MB, Jadranin MB, Vasić VM. Investigation of reaction between quercetin and Au(iii) in acidic media: mechanism and identification of reaction products. NEW J CHEM 2013. [DOI: 10.1039/c2nj40742f] [Citation(s) in RCA: 14] [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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Čolović MB, Bajuk-Bogdanović DV, Avramović NS, Holclajtner-Antunović ID, Bošnjaković-Pavlović NS, Vasić VM, Krstić DZ. Inhibition of rat synaptic membrane Na+/K+-ATPase and ecto-nucleoside triphosphate diphosphohydrolases by 12-tungstosilicic and 12-tungstophosphoric acid. Bioorg Med Chem 2011; 19:7063-9. [DOI: 10.1016/j.bmc.2011.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 09/30/2011] [Accepted: 10/04/2011] [Indexed: 11/25/2022]
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Abstract
The aim of this work was to investigate the influence of [PdCl4]2-, [PdCl(dien)]+ and [PdCl(Me4dien)]+ complexes on Na+ / K+-ATPase activity. The dose-dependent inhibition curves were obtained in all cases. IC50 values determined by Hill analysis were 2.25 x 10(-5) M, 1.21 x 10(-4) M and 2.36 x 10(-4) M, respectively. Na+ / K+-ATPase exhibited typical Michelis-Menten kinetics in the presence of Pd(II) complexes. Kinetic parameters (Vmax, Km) derived using Eadie-Hofstee transformation indicated a noncompetitive type of Na+ / K+-ATPase inhibition. The inhibitor constants (Ki) were determined from Dixon plots. The order of complex affinity for binding with Na+ / K+-ATPase, deducted from Ki values, was [PdCl4]2- > [PdCl(dien)]+ > [PdCl(Me4dien)]+. The results indicated that the potency of Pd(II) complexes to inhibit Na+/ K +-ATPase activity depended strongly on ligands of the related compound. Furthermore, the ability of SH-donor ligands, L-cysteine and glutathione, to prevent and recover the Pd(II) complexes-induced inhibition of Na+ / K+-ATPase was examined. The addition of 1 mM L-cysteine or glutathione to the reaction mixture before exposure to Pd(II) complexes prevented the inhibition by increasing the IC50 values by one order of magnitude. Moreover, the inhibited enzymatic activity was recovered by addition of SH-donor ligands in a concentration-dependent manner.
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Affiliation(s)
- Katarina S Krinulović
- Vinca Institute of Nuclear Sciences, Department of Physical Chemistry, P.O. Box 522, Belgrade 11001, Serbia & Montenegro
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Cakar MM, Vasić VM, Petkovska LT, Stojić DL, Avramov-Ivić M, Milovanović GA. Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators. J Pharm Biomed Anal 1999; 20:655-62. [PMID: 10704134 DOI: 10.1016/s0731-7085(99)00056-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Newly synthesized oximes, mono and bis imidazole derivatives, which promise to be more effective acetylcholinesterase reactivators than standard antidotes used, were investigated by spectrophotometric and electrochemical methods. The electrochemical investigations confirmed the existence of overlapping equilibria, obtained by spectrophotometric methods. Dissociation constants of those oximes were also obtained by numerical treatment of overlapping equilibria, using the Lavendberg Marquardt least square method, and when compared with the same for some similar compounds, were found to be very effective acetylcholinesterase reactivators. The distribution of ionic forms of the investigated oximes, as a dependence of pH values, was calculated from the obtained values of dissociation constants. The results indicated that many oxime anions will be available at physiological pH 7.4 and a relative increased ability to reactivate inhibited acetylcholinesterase could be expected.
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Affiliation(s)
- M M Cakar
- Faculty of Pharmacy, University of Belgrade, Yugoslavia
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Dumanović D, Juranić I, Dzeletović D, Vasić VM, Jovanović J. Protolytic constants of nizatidine, ranitidine and N,N'-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation. J Pharm Biomed Anal 1997; 15:1667-78. [PMID: 9260662 DOI: 10.1016/s0731-7085(96)01977-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [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: 02/05/2023]
Abstract
The prototropic exchange equilibria of two drugs, nizatidine (I) and ranitidine(II), and also of structurally related the N,N'-dimethyl-2-nitro-1,1-ethenediamine molecule (III) were investigated. From the changes in electronic spectra in media of various acidity several protonation constants were determined. For pK values were -0.82, 1.95, and 6.67; for ranitidine pK values were 1.95 and 8.13; and for III was 2.60. The hydroxylation equilibrium constant in strongly alkaline media was determined too. Corresponding pK(a) values were 13.23 for I, 13.36 for II and 13.76 for III. Molecular orbital calculations of electronic spectra confirmed that pK 1.95 for I and II, and pK 2.60 for III, are associated with C-protonation of nitroethenediamine fragment, while all pK(a) values correspond to the addition of HO- anion at the same double bond.
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Affiliation(s)
- D Dumanović
- ICN Galenika Institute, Belgrade, Yugoslavia
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Tošić MS, Vasić VM, Nedeljković JM, Ilić LA. Influence of sodium dodecyl sulfate micelles on the kinetics of complex formation between Pd(H2O)42+ and glutathione. Polyhedron 1997. [DOI: 10.1016/s0277-5387(96)00373-7] [Citation(s) in RCA: 9] [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: 10/27/2022]
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Abstract
The influence of the acidity and the Cl- concentration on the kinetics of the complex formation between s-carboxymethyl-L-cysteine and Pd(II) chloride was studied with a stopped-flow technique in the pH range from 1.5 to 5.0 at 25 degrees C. The reaction mechanism involving Pd(H2O)4-nCln, LH-, LH2 and LH3+ species was proposed. Fairly good agreement between the computed and experimentally determined rate constants was found.
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