1
|
Gnoth K, Bär JW, Rosche F, Rahfeld JU, Demuth HU. Contribution of amino acids in the active site of dipeptidyl peptidase 4 to the catalytic action of the enzyme. PLoS One 2024; 19:e0289239. [PMID: 38625918 PMCID: PMC11020753 DOI: 10.1371/journal.pone.0289239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 07/12/2023] [Accepted: 01/22/2024] [Indexed: 04/18/2024] Open
Abstract
Dipeptidyl peptidase 4 (DP4)/CD26 regulates the biological function of various peptide hormones by releasing dipeptides from their N-terminus. The enzyme is a prominent target for the treatment of type-2 diabetes and various DP4 inhibitors have been developed in recent years, but their efficacy and side effects are still an issue. Many available crystal structures of the enzyme give a static picture about enzyme-ligand interactions, but the influence of amino acids in the active centre on binding and single catalysis steps can only be judged by mutagenesis studies. In order to elucidate their contribution to inhibitor binding and substrate catalysis, especially in discriminating the P1 amino acid of substrates, the amino acids R125, N710, E205 and E206 were investigated by mutagenesis studies. Our studies demonstrated, that N710 is essential for the catalysis of dipeptide substrates. We found that R125 is not important for dipeptide binding but interacts in the P1`position of the peptide backbone. In contrast to dipeptide substrates both amino acids play an essential role in the binding and arrangement of long natural substrates, particularly if lacking proline in the P1 position. Thus, it can be assumed that the amino acids R125 and N710 are important in the DP4 catalysed substrate hydrolysis by interacting with the peptide backbone of substrates up- and downstream of the cleavage site. Furthermore, we confirmed the important role of the amino acids E205 and E206. However, NP Y, displaying proline in P1 position, is still processed without the participation of E205 or E206.
Collapse
Affiliation(s)
- Kathrin Gnoth
- Department of Applied Biosciences and Process Engineering, Hochschule Anhalt, Köthen, Germany
| | - Joachim Wolfgang Bär
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biopharmaceuticals Cell Culture & DP, Biberach/Riß, Germany
| | - Fred Rosche
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle, Germany
| | - Jens-Ulrich Rahfeld
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Halle, Germany
| | - Hans-Ulrich Demuth
- Department of Applied Biosciences and Process Engineering, Hochschule Anhalt, Köthen, Germany
| |
Collapse
|
2
|
Kirchberg M, Eick S, Buchholz M, Rosche F, Kiesow A, Sarembe S, Mäder K. Controlled release minocycline-lipid-complex extrudates for the therapy of periodontitis with enhanced flexibility. Int J Pharm 2020; 586:119578. [PMID: 32615242 DOI: 10.1016/j.ijpharm.2020.119578] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 11/16/2022]
Abstract
We describe the development of flexible minocycline-lipid-complex extrudates with optimized mechanical and drug release properties. These extrudates contain a minocycline - magnesium stearate chelate complex with a higher stability in aqueous media, which has now been incorporated in a PEG-PLGA (polyethylene glycol - poly(lactic-co-glycolic acid)) matrix. PEG 1500 has been utilized in different concentrations to serve as plasticizer. The novel formulations have been characterized by texture analysis, X-Ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). Extrudates with a reduced diameter of 300 µm (previously 600 µm) were introduced, and a more sensitive quantification method with a tandem-mass spectrometry detector was developed. From all tested formulations, the extrudates consisting of Expansorb DLG 50 - 6P (PEG-PLGA, molar weight 30-60 kDa) paired with 10% PEG 1500 emerged as best formulation. These extrudates feature a drug content of 11.5% and a controlled release over at least 42 days. The release profile is without a lag time and shows initially a slightly higher release rate, which is desired. Compared to previous developments, the extrudates now offer a high flexibility combined with a large mechanical resilience, which will ease the handling and administration.
Collapse
Affiliation(s)
- Martin Kirchberg
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, 06120 Halle (Saale), Germany.
| | - Sigrun Eick
- School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland.
| | - Mirko Buchholz
- Fraunhofer Institute for Cell Therapy and Immunology IZI, Drug Design and Analytical Chemistry, Weinbergweg 22, 06120 Halle (Saale), Germany; Periotrap Pharmaceuticals GmbH, Weinbergweg 22, 06120 Halle (Saale), Germany.
| | - Fred Rosche
- Fraunhofer Institute for Cell Therapy and Immunology IZI, Drug Design and Analytical Chemistry, Weinbergweg 22, 06120 Halle (Saale), Germany.
| | - Andreas Kiesow
- Fraunhofer Institute for Microstructures and Materials IMWS, Characterization of Medical and Cosmetic Products, Walter-Hülse-Strasse 1, 06120 Halle (Saale), Germany.
| | - Sandra Sarembe
- Fraunhofer Institute for Microstructures and Materials IMWS, Characterization of Medical and Cosmetic Products, Walter-Hülse-Strasse 1, 06120 Halle (Saale), Germany.
| | - Karsten Mäder
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, 06120 Halle (Saale), Germany.
| |
Collapse
|
3
|
Stephan A, Hahn-Löbmann S, Rosche F, Buchholz M, Giritch A, Gleba Y. Simple Purification of Nicotiana benthamiana-Produced Recombinant Colicins: High-Yield Recovery of Purified Proteins with Minimum Alkaloid Content Supports the Suitability of the Host for Manufacturing Food Additives. Int J Mol Sci 2017; 19:E95. [PMID: 29286298 PMCID: PMC5796045 DOI: 10.3390/ijms19010095] [Citation(s) in RCA: 15] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/20/2017] [Accepted: 12/22/2017] [Indexed: 12/04/2022] Open
Abstract
Colicins are natural non-antibiotic bacterial proteins with a narrow spectrum but an extremely high antibacterial activity. These proteins are promising food additives for the control of major pathogenic Shiga toxin-producing E. coli serovars in meats and produce. In the USA, colicins produced in edible plants such as spinach and leafy beets have already been accepted by the U. S. Food and Drug Administration (FDA) and U. S. Department of Agriculture (USDA) as food-processing antibacterials through the GRAS (generally recognized as safe) regulatory review process. Nicotiana benthamiana, a wild relative of tobacco, N. tabacum, has become the preferred production host plant for manufacturing recombinant proteins-including biopharmaceuticals, vaccines, and biomaterials-but the purification procedures that have been employed thus far are highly complex and costly. We describe a simple and inexpensive purification method based on specific acidic extraction followed by one chromatography step. The method provides for a high recovery yield of purified colicins, as well as a drastic reduction of nicotine to levels that could enable the final products to be used on food. The described purification method allows production of the colicin products at a commercially viable cost of goods and might be broadly applicable to other cost-sensitive proteins.
Collapse
Affiliation(s)
- Anett Stephan
- Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany.
| | | | - Fred Rosche
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation, D-06120 Halle (Saale), Germany.
| | - Mirko Buchholz
- Fraunhofer Institute for Cell Therapy and Immunology, Department for Drug Design and Target Validation, D-06120 Halle (Saale), Germany.
| | - Anatoli Giritch
- Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany.
| | - Yuri Gleba
- Nomad Bioscience GmbH, Biozentrum Halle, D-06120 Halle (Saale), Germany.
| |
Collapse
|
4
|
Rosche F, Heckmann G, Weller F, Fluck E. Ein neuer Heterocyclus, 2λ3,4λ5-[1,2,4]-Oxadiphosphinin (2), als Ligand eines zweikernigen Eisenkomplexes / A New Heterocycle, 2λ3, 4λ5 -[1,2,4]-Oxadiphosphinine (2), as Ligand of a Binuclear Iron Complex. Zeitschrift für Naturforschung B 2014. [DOI: 10.1515/znb-1996-1209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Preparation and properties of a coordination compound are described, in which a carbonyl group in bis[(dicarbonyl)(μ5-cyclopentadienyl)iron] is substituted by hitherto unknown octa- N-methyl-2λ3,4λ5-[1,2,4]-oxadiphosphinine-2,4,4,6-tetramine (2). The 1H , 31P, and 13C NMR spectra are recorded and discussed in detail. The molecular structure of the iron complex 4 is described and interpreted.
Collapse
Affiliation(s)
- Fred Rosche
- Institut für Anorganische Chemie der Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart
| | - Gernot Heckmann
- Institut für Anorganische Chemie der Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart
| | - Frank Weller
- Fachbereich Chemie der Universität Marburg, Hans Meerweinstraße, D-35043 Marburg
| | - Ekkehard Fluck
- Gmelin-Institut für Anorganische Chemie und Grenzgebiete der Max-Planck-Gesellschaft, Varrentrappstraße 40/42, D-60486 Frankfurt
| |
Collapse
|
5
|
Wagner L, Wermann M, Rosche F, Rahfeld JU, Hoffmann T, Demuth HU. Isolation of dipeptidyl peptidase IV (DP 4) isoforms from porcine kidney by preparative isoelectric focusing to improve crystallization. Biol Chem 2011; 392:665-77. [DOI: 10.1515/bc.2011.068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
AbstractIn the present studies we resolved the post-translational microheterogeneity of purified porcine dipeptidyl peptidase IV (DP 4) from kidney cortex. Applying SDS-homogeneous DP 4 onto an analytical agarose isoelectric focusing (IEF) gel, pH 4–6, activity staining resulted in at least 17 isoforms between pH 4.8–6.0. These could be separated into fractions with only two to six isoforms by means of preparative liquid-phase IEF, using a Rotofor cell. Starting off with three parallel Rotofor runs under the same conditions at pH 5–6, the fractions were pooled according to the specific activity of DP 4, pH and analytical IEF profile, and further refractionated without any additional ampholytes. Since excessive dilution of ampholytes and proteins was kept to the minimum, a second refractionation step could be introduced, resulting in pH gradients between 0.022 and 0.028 pH increments per fraction. By performing two consecutive refractionation steps, the high resolution necessary for the separation of DP 4 isoforms could be achieved. This represents an alternative method if isolation of isoforms with similar pI's results in precipitation and denaturation in presence of a narrow pH range. Furthermore, it demonstrates that preparative IEF is a powerful tool to resolve post-translational microheterogeneity of a purified protein required for crystallization processing.
Collapse
|
6
|
Böhme L, Bär JW, Hoffmann T, Manhart S, Ludwig HH, Rosche F, Demuth HU. Isoaspartate residues dramatically influence substrate recognition and turnover by proteases. Biol Chem 2008. [DOI: 10.1515/bc.2008.123_bchm.just-accepted] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
7
|
Böhme L, Bär JW, Hoffmann T, Manhart S, Ludwig HH, Rosche F, Demuth HU. Isoaspartate residues dramatically influence substrate recognition and turnover by proteases. Biol Chem 2008; 389:1043-53. [DOI: 10.1515/bc.2008.123] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Posttranslational modifications influence the structure, stability and biological activity of proteins. Most of the reactions are enzyme-catalyzed, but some, such as asparagine (Asn) and glutamine (Gln) deamidation and the isoaspartate (isoAsp) formation within peptide chains, occur spontaneously. It has been previously shown that certain peptide sequences form isoAsp quite fast if the Asp stretches are exposed to the protein surface, thereby potentially changing susceptibility to proteolysis at these sites. This tempted us to investigate the activity of exo- and endopeptidases against Asp- or isoAsp-containing substrates. Members of the prolyl oligopeptidase family were unable to cleave substrates after proline if isoAsp was placed in the P2-position. Caspases, usually accepting Asp at P1-position of their substrates, did not cleave isoAsp-containing sequences. Similarly, the metal-dependent aminopeptidase amino peptidase N did not turnover N-terminal isoAsp-containing substrates, nor could the endopeptidase matrix metalloproteinase 3 (MMP 3) hydrolyze a serum amyloid A protein-like substrate if the sequence contained isoAsp instead of Asp. Also, the highly specific enterokinase, usually clipping after a stretch of four Asp residues and a lysine in the P1 position, could not turnover substrates if the P2 amino acid was replaced by isoAsp. In contrast, acylamino acid-releasing enzyme and dipeptidyl peptidases 1, 2 and 4 hydrolyzed substrates containing the isoAsp-Ala motif.
Collapse
|
8
|
Heckmann G, Rosche F, Weller F, Fluck E. REACTION OF 1,1,3,3-TETRAKIS(DIMETHYLAMINO)-1λ5,3λ5-DIPHOSPHETE, 1, WITH CARBONDISULFIDE II. DIHYDRO-λ5-PHOSPHETES; NMR ISOTOPE EFFECTS. PHOSPHORUS SULFUR 2006. [DOI: 10.1080/10426509608037950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Gernot Heckmann
- a Institut für Anorganische Chemie der Universität Stuttgart , Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Fred Rosche
- a Institut für Anorganische Chemie der Universität Stuttgart , Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Frank Weller
- b Fachbereich Chemie der Universität Marburg , Hans-Meerwein-Straβe, D-35043, Marburg/Lahn, Germany
| | - Ekkehard Fluck
- c Gmelin-Institut für Anorganische Chemie der Max-Planck-Gesellschaft , Varrentrappstr. 40/42, D-60486, Frankfurt (Main), Germany
| |
Collapse
|
9
|
Jurkschat K, Rosche F, Schurmann M. UNEXPECTED FORMATION AND MOLECULAR STRUCTURE OF 2,2,6,6-TETRA-t-BUTYL-4,8-DIMETHYL-1,5,9-TRIOXA-4,8-DISILA-2,6-DISTANNABICYCLO[3.3.1]NONANE. PHOSPHORUS SULFUR 2006. [DOI: 10.1080/10426509608037963] [Citation(s) in RCA: 5] [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: 10/23/2022]
Affiliation(s)
- Klaus Jurkschat
- a Fachbereich Chemie der Universität Dortmund, Lehrstuhl für Anorganische Chemie II , D-4421, Dortmund, Germany
| | - Fred Rosche
- a Fachbereich Chemie der Universität Dortmund, Lehrstuhl für Anorganische Chemie II , D-4421, Dortmund, Germany
| | - Markus Schurmann
- a Fachbereich Chemie der Universität Dortmund, Lehrstuhl für Anorganische Chemie II , D-4421, Dortmund, Germany
| |
Collapse
|
10
|
Wolf R, Hoffmann T, Rosche F, Demuth HU. Simultaneous determination of incretin hormones and their truncated forms from human plasma by immunoprecipitation and liquid chromatography–mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2004; 803:91-9. [PMID: 15026002 DOI: 10.1016/j.jchromb.2003.11.044] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [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: 11/26/2022]
Abstract
The incretins, glucose-dependent insulinotropic peptide (GIP(1-42)) and glucagon-like peptide 1 (GLP-1(7-36)), are involved in regulation of gastric emptying, glucose homeostasis, body fat regulation and the glucose-induced insulin secretion from the endocrine pancreas. After release in the circulation both peptides are rapidly degraded by the exopeptidase dipeptidyl peptidase IV (DP IV) to the inactive polypeptides GIP(3-42) and GLP-1(9-36). In vivo stabilization of the active incretins by orally available DP IV-inhibitors is now widely accepted as a new therapeutic approach in antidiabetic treatment. In order to demonstrate the pharmacodynamic effect of DP IV-inhibitors, it is necessary to measure the plasma levels of active and inactive forms of GIP and GLP-1. We previously described an immunoprecipitation method as sample preparation and concentration in combination with a LC-MS analysis for determination of active and inactive GIP. We could improve the efficiency and suitability of this method by reduction of the necessary sample volume to 1.0 ml and simultaneous measurement of GIP(1-42), GIP(3-42) and GLP-1(7-36), GLP-1(9-36), without loss of sensitivity. An LOQ of approximately 5 and 11 pmol/l was maintained for GIP and GLP-1, respectively.
Collapse
Affiliation(s)
- Raik Wolf
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany
| | | | | | | |
Collapse
|
11
|
Baer JW, Gerhartz B, Hoffmann T, Rosche F, Demuth HU. Characterisation of human DP IV produced by a Pichia pastoris expression system. Adv Exp Med Biol 2003; 524:103-8. [PMID: 12675229 DOI: 10.1007/0-306-47920-6_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
|
12
|
Hinke SA, Lynn F, Ehses J, Pamir N, Manhart S, Kühn-Wache K, Rosche F, Demuth HU, Pederson RA, McIntosh CHS. Glucose-dependent insulinotropic polypeptide (GIP): development of DP IV-resistant analogues with therapeutic potential. Adv Exp Med Biol 2003; 524:293-301. [PMID: 12675251 DOI: 10.1007/0-306-47920-6_35] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- Simon A Hinke
- Department of Physiology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Hinke SA, Gelling R, Manhart S, Lynn F, Pederson RA, Kühn-Wache K, Rosche F, Demuth HU, Coy D, McIntosh CHS. Structure-activity relationships of glucose-dependent insulinotropic polypeptide (GIP). Biol Chem 2003; 384:403-7. [PMID: 12715891 DOI: 10.1515/bc.2003.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [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: 02/06/2023]
Abstract
Six GIP(1-NH2) analogs were synthesized with modifications (de-protonation, N-methylation, reversed chirality, and substitution) at positions 1, 3, and 4 of the N-terminus, and additionally, a cyclized GIP derivative was synthesized. The relationship between altered structure to biological activity was assessed by measuring receptor binding affinity and ability to stimulate adenylyl cyclase in CHO-K1 cells transfected with the wild-type GIP receptor (wtGIPR). These structure-activity relationship studies demonstrate the importance of the GIP N-terminus and highlight structural constraints that can be introduced in GIP analogs. These analogs may be useful starting points for design of peptides with enhanced in vivo bioactivity.
Collapse
Affiliation(s)
- Simon A Hinke
- Department of Physiology, University of British Columbia, Vancouver, B.C., Canada V6T 1Z3
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Beckmann J, Horn D, Jurkschat K, Rosche F, Schürmann M, Zachwieja U, Dakternieks D, Duthie A, Lim A. Triorganotin Fluoride Structures: A Ligand Close-Packing Model with Predominantly Ionic Sn−F Bonds. Eur J Inorg Chem 2003. [DOI: 10.1002/ejic.200390022] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
15
|
Schilling S, Hoffmann T, Rosche F, Manhart S, Wasternack C, Demuth HU. Heterologous expression and characterization of human glutaminyl cyclase: evidence for a disulfide bond with importance for catalytic activity. Biochemistry 2002; 41:10849-57. [PMID: 12196024 DOI: 10.1021/bi0260381] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [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: 11/30/2022]
Abstract
Glutaminyl cyclase (QC, EC 2.3.2.5) catalyzes the formation of pyroglutamate residues from glutamine at the N-terminus of peptides and proteins. In the current study, human QC was functionally expressed in the secretory pathway of Pichia pastoris, yielding milligram quantities after purification from the supernatant of a 5 L fermentation. Initial characterization studies of the recombinant QC using MALDI-TOF mass spectrometry revealed correct proteolytic processing and N-glycosylation at both potential sites with similar 2 kDa extensions. CD spectral analysis indicated a high alpha-helical content, which contrasts with plant QC from Carica papaya. The kinetic parameters for conversion of H-Gln-Tyr-Ala-OH by recombinant human QC were almost identical to those previously reported for purified bovine pituitary QC. However, the results obtained for conversion of H-Gln-Gln-OH, H-Gln-NH2, and H-Gln-AMC were found to be contradictory to previous studies on human QC expressed intracellularly in E. coli. Expression of QC in E. coli showed that approximately 50% of the protein did not contain a disulfide bond that is present in the entire QC expressed in P. pastoris. Further, the enzyme was consistently inactivated by treatment with 15 mM DTT, whereas deglycosylation had no effect on enzymatic activity. Analysis of the fluorescence spectra of the native, reduced, and unfolded human QC point to a conformational change of the protein upon treatment with DTT. In terms of the different enzymatic properties, the consequences of QC expression in different environments are discussed.
Collapse
Affiliation(s)
- Stephan Schilling
- Laboratory of Biochemistry, Probiodrug AG, Weinbergweg 22, 06120 Halle/Saale, Germany
| | | | | | | | | | | |
Collapse
|
16
|
Raith K, Kühn AV, Rosche F, Wolf R, Neubert RHH. Characterization of povidone products by means of 13C-NMR, MALDI-TOF, and electrospray mass spectrometry. Pharm Res 2002; 19:556-60. [PMID: 12033395 DOI: 10.1023/a:1015172402248] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Klaus Raith
- Martin Luther University Halle-Wittenberg, Institute of Pharmaceutics and Biopharmaceutics, Halle, Germany.
| | | | | | | | | |
Collapse
|
17
|
Wolf R, Rosche F, Hoffmann T, Demuth HU. Immunoprecipitation and liquid chromatographic-mass spectrometric determination of the peptide glucose-dependent insulinotropic polypeptides GIP1-42 and GIP3-42 from human plasma samples. New sensitive method to analyze physiological concentrations of peptide hormones. J Chromatogr A 2001; 926:21-7. [PMID: 11554413 DOI: 10.1016/s0021-9673(01)00942-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [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: 11/24/2022]
Abstract
The gastrointestinal peptide glucose-dependent insulinotropic polypeptide (GIP1-42) is one of the incretin hormones regulating glucose-induced insulin secretion from the endocrine pancreas. GIP1-42 is a substrate of the circulating enzyme dipeptidyl peptidase IV, which removes the N-terminal peptide Tyr-Ala resulting in the inactive polypeptide GIP3-42. Hither to existing immunoassays do not enable a separate quantification of active and inactive forms, respectively. Therefore, we developed a highly specific and sensitive LC-MS assay for the identification and quantification of GIP1-42 and GIP3-42. Total GIP was immunoprecipitated from crude plasma samples using a C-terminally directed antibody. Thus, peptides were purified and concentrated prior to LC-MS analysis. The present immunoprecipitation-LC-MS assay enables the quantification of active and inactive GIP over a concentration range from 5 to 350 pmol/l in human plasma samples. Since this range covers the basal and postprandial levels of GIP the method is applicable to the determination of concentration changes and changes in the ratio of active and inactive forms of GIP in human plasma.
Collapse
Affiliation(s)
- R Wolf
- Probiodrug GmbH, Halle, Germany
| | | | | | | |
Collapse
|
18
|
Rosche F, Schmidt J, Hoffmann T, Pauly RP, McIntosh CH, Pederson RA, Demuth HU. Kinetic analysis of enzymatic and nonenzymatic degradation of peptides by MALDI-TOFMS. Methods Mol Biol 2001; 146:251-72. [PMID: 10948507 DOI: 10.1385/1-59259-045-4:251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- F Rosche
- Department of Physiology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | | |
Collapse
|
19
|
Pospisilik JA, Hinke SA, Pederson RA, Hoffmann T, Rosche F, Schlenzig D, Glund K, Heiser U, McIntosh CH, Demuth H. Metabolism of glucagon by dipeptidyl peptidase IV (CD26). Regul Pept 2001; 96:133-41. [PMID: 11111019 DOI: 10.1016/s0167-0115(00)00170-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Glucagon is a 29-amino acid polypeptide released from pancreatic islet alpha-cells that acts to maintain euglycemia by stimulating hepatic glycogenolysis and gluconeogenesis. Despite its importance, there remains controversy about the mechanisms responsible for glucagon clearance in the body. In the current study, enzymatic metabolism of glucagon was assessed using sensitive mass spectrometric techniques to identify the molecular products. Incubation of glucagon with purified porcine dipeptidyl peptidase IV (DP IV) yielded sequential production of glucagon(3-29) and glucagon(5-29). In human serum, degradation to glucagon(3-29) was rapidly followed by N-terminal cyclization of glucagon, preventing further DP IV-mediated hydrolysis. Bioassay of glucagon, following incubation with purified DP IV or normal rat serum demonstrated a significant loss of hyperglycemic activity, while a similar incubation in DP IV-deficient rat serum did not show any loss of glucagon bioactivity. Degradation, monitored by mass spectrometry and bioassay, was blocked by the specific DP IV inhibitor, isoleucyl thiazolidine. These results identify DP IV as a primary enzyme involved in the degradation and inactivation of glucagon. These findings have important implications for the determination of glucagon levels in human plasma.
Collapse
Affiliation(s)
- J A Pospisilik
- Department of Physiology, University of British Columbia, British Columbia, V6T 1Z3, Vancouver, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Pauly RP, Demuth HU, Rosche F, Schmidt J, White HA, Lynn F, McIntosh CH, Pederson RA. Improved glucose tolerance in rats treated with the dipeptidyl peptidase IV (CD26) inhibitor Ile-thiazolidide. Metabolism 1999; 48:385-9. [PMID: 10094118 DOI: 10.1016/s0026-0495(99)90090-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The incretins glucose-dependent insulinotropic polypeptide (GIP1-42) and truncated forms of glucagon-like peptide-1 (GLP-1) are hormones released from the gut in response to ingested nutrients, which act on the pancreas to potentiate glucose-induced insulin secretion. These hormones are rapidly inactivated by the circulating enzyme dipeptidyl peptidase IV ([DPIV] CD26). This study describes the effect on glucose tolerance and insulin secretion of inhibiting endogenous DPIV in the rat using Ile-thiazolidide, a specific DPIV inhibitor. High-performance liquid chromatography (HPLC) analysis of plasma following in vivo administration of 125I-labeled peptides showed that inhibition of DPIV by about 70% prevented the degradation of 90.0% of injected 125I-GLP-17-36 after 5 minutes, while only 13.4% remained unhydrolyzed in rats not treated with the DPIV-inhibiting agent after only 2 minutes. Ile-thiazolidide treatment also increased the circulating half-life of intact GLP-17-36 released in response to intraduodenal (ID) glucose (as measured by N-terminal specific radioimmunoassay [RIA]). In addition, inhibition of DPIV in vivo resulted in an earlier increase and peak of plasma insulin and a more rapid clearance of blood glucose in response to ID glucose challenge. When considered with the HPLC data, these results suggest that the altered insulin profile is an incretin-mediated response. DPIV inhibition resulting in improved glucose tolerance may have therapeutic potential for the management of type 2 diabetes mellitus.
Collapse
Affiliation(s)
- R P Pauly
- Department of Physiology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Pauly RP, Rosche F, Wermann M, McIntosh CH, Pederson RA, Demuth HU. Investigation of glucose-dependent insulinotropic polypeptide-(1-42) and glucagon-like peptide-1-(7-36) degradation in vitro by dipeptidyl peptidase IV using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. A novel kinetic approach. J Biol Chem 1996; 271:23222-9. [PMID: 8798518 DOI: 10.1074/jbc.271.38.23222] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.6] [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: 02/02/2023] Open
Abstract
The incretins glucose-dependent insulinotropic polypeptide (GIP1-42) and glucagon-like peptide-1-(7-36)-amide (GLP-17-36), hormones that potentiate glucose-induced insulin secretion from the endocrine pancreas, are substrates of the circulating exopeptidase dipeptidyl peptidase IV and are rendered biologically inactive upon cleavage of their N-terminal dipeptides. This study was designed to determine if matrix-assisted laser desorption/ionization-time of flight mass spectrometry is a useful analytical tool to study the hydrolysis of these hormones by dipeptidyl peptidase IV, including kinetic analysis. Spectra indicated that serum-incubated peptides were cleaved by this enzyme with only minor secondary degradation due to other serum protease activity. Quantification of the mass spectrometric signals allowed kinetic constants for both porcine kidney- and human serum dipeptidyl peptidase IV-catalyzed incretin hydrolysis to be calculated. The binding constants (Km) of these incretins to purified porcine kidney-derived enzyme were 1.8 +/- 0.3 and 3.8 +/- 0.3 microM, whereas the binding constants observed in human serum were 39 +/- 29 and 13 +/- 9 microM for glucose-dependent-insulinotropic polypeptide and glucagon-like peptide-1-(7-36)-amide respectively. The large range of Km values found in human serum suggests a heterogeneous pool of enzyme. The close correlation between the reported kinetic constants and those previously described validates this novel approach to kinetic analysis.
Collapse
Affiliation(s)
- R P Pauly
- Department of Physiology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | | | | | | | | |
Collapse
|
22
|
Rosche F, Heckmann G, Neum�ller B, Fluck E. �bergangsmetall-Komplexe des 1,1,3,3-Tetrakis(dimethylamino)-1?5,3?5-diphosphets. Z Anorg Allg Chem 1996. [DOI: 10.1002/zaac.19966220605] [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: 11/11/2022]
|
23
|
|
24
|
Rosche F, Heckmann G, Fluck E, Neum�ller B. Reactions of 1,1,3,3-tetrakis(dimethylamino)-1?5,3?5-diphosphete with diphenylchlorophosphane and methyl iodide. Heteroat Chem 1996. [DOI: 10.1002/(sici)1098-1071(199610)7:5<341::aid-hc9>3.0.co;2-e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
25
|
Fluck E, Heckmann G, Rosche F, Westerhausen M, Gorbunowa E. Die Reaktion von ?5-Diphospheten mit COS und CO2 Dihydro-?5-Phosphete. Z Anorg Allg Chem 1995. [DOI: 10.1002/zaac.19956210918] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
|