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Gao XM, Ye YH, Bernd M, Kutscher B. Studies on the synthesis of cyclic pentapeptides as LHRH antagonists and the factors that influence cyclization yield. J Pept Sci 2002; 8:418-30. [PMID: 12212805 DOI: 10.1002/psc.397] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Six cyclic pentapeptides containing two or three non-protein amino acids have been synthesized by cyclization of linear precursors in dilute solution and characterized by TLC. HPLC, NMR, melting point. specific rotation etc. A total of 72 cyclization reactions were carried out to study the factors that influence head-to-tail cyclization: linear precursor sequence, coupling reagent, residue configuration, the proportion of DMAP additive, concentration, reaction temperature and reaction time. The cyclic pentapeptides will be modified by active moieties and evaluated as LHRH antagonists.
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MESH Headings
- Amino Acid Sequence
- Chromatography, High Pressure Liquid
- Chromatography, Thin Layer
- Gonadotropin-Releasing Hormone/antagonists & inhibitors
- Indicators and Reagents
- Nuclear Magnetic Resonance, Biomolecular
- Oligopeptides/chemical synthesis
- Oligopeptides/chemistry
- Oligopeptides/pharmacology
- Peptides, Cyclic/chemical synthesis
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/pharmacology
- Spectrometry, Mass, Electrospray Ionization
- Spectrometry, Mass, Fast Atom Bombardment
- Temperature
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Affiliation(s)
- Xing-Ming Gao
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering, Ministry of Education, Department of Chemistry, Peking University, Beijing, China
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Befus AD, Mowat C, Gilchrist M, Hu J, Solomon S, Bateman A. Neutrophil Defensins Induce Histamine Secretion from Mast Cells: Mechanisms of Action. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.2.947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Defensins are endogenous antimicrobial peptides stored in neutrophil granules. Here we report that a panel of defensins from human, rat, guinea pig, and rabbit neutrophils all have histamine-releasing activity, degranulating rat peritoneal mast cells with EC50 ranging from 70 to 2500 nM, and between 45 and 60% of the total histamine released. The EC50 for defensin-induced histamine secretion correlates with their net basic charge at neutral pH. There is no correlation between histamine release and antimicrobial potency. Degranulation induced by defensins has characteristics similar to those of activation by substance P. The maximum percent histamine release is achieved in <10 s, and it can be markedly inhibited by pertussis toxin (100 ng/ml) and by pretreatment of mast cells with neuraminidase. These properties differ from those for degranulation induced by IgE-dependent Ag stimulation and by the calcium ionophore A23187. GTPase activity, a measure of G protein activation, was induced in a membrane fraction from mast cells following treatment with defensin. Thus, neutrophil defensins are potent mast cell secretagogues that act in a manner similar to substance P and 48/80, through a rapid G protein-dependent response that is mechanistically distinct from Ag/IgE-dependent mast cell activation. Defensins may provide important pathways for communication between neutrophils and mast cells in defenses against microbial agents and in acute inflammatory responses.
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Affiliation(s)
- A. Dean Befus
- *Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Connie Mowat
- †Immunology Research Group, University of Calgary, Calgary, Alberta, Canada; and
| | - Mark Gilchrist
- *Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Jing Hu
- ‡Department of Medicine, Obstetrics and Gynecology, Endocrine Laboratory, Royal Victoria Hospital/McGill University, Montreal, Quebec, Canada
| | - Samuel Solomon
- ‡Department of Medicine, Obstetrics and Gynecology, Endocrine Laboratory, Royal Victoria Hospital/McGill University, Montreal, Quebec, Canada
| | - Andrew Bateman
- ‡Department of Medicine, Obstetrics and Gynecology, Endocrine Laboratory, Royal Victoria Hospital/McGill University, Montreal, Quebec, Canada
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Kutscher B, Bernd M, Beckers T, Polymeropoulos EE, Engel J. Chemie und Molekularbiologie bei der Suche nach neuen LHRH-Antagonisten. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971092005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Janecka A, Janecki T, Bowers C, Folkers K. Antide B, an antagonist of LHRH with cis-3-(4-pyrazinylcarbonylaminocyclohexyl)alanine in position 5. Amino Acids 1995; 8:89-96. [DOI: 10.1007/bf00806547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/1994] [Accepted: 05/25/1994] [Indexed: 10/26/2022]
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Chapter 18. Gonadotropin Releasing Hormone Antagonists. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1995. [DOI: 10.1016/s0065-7743(08)60931-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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