| Mass spectrometric and kinetic studies on slow progression of papain-catalyzed polymerization of L-glutamic acid diethyl ester. | |
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MedLine Citation:
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PMID: 18405672 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Papain polymerizes L-glutamic acid diethyl ester (Glu-di-OEt) regioselectively, resulting in the formation of poly (gamma-ethyl alpha-L-glutamic acid) with various degrees of polymerization of less than 13. Reaction temperatures below 20 degrees C were appropriate for the reaction in terms of suppression of non-enzymatic degradation of Glu-di-OEt and an increase in the peptide yield, while the reaction was preceded by a pronounced induction period. Mass spectrometric analyses of the reaction conducted at 0 degrees C revealed that the accumulation of the initial dimerization product, L-glutamyl-L-glutamic acid triethyl ester (Glu-Glu-tri-OEt), was limited during the induction period, and that a sequential polymer derived from a further elongation of the dimer was the tetramer, but not the trimer. Kinetic analyses of acyl transfer reactions with Glu-di-OEt and Glu-Glu-tri-OEt as acyl acceptors and Nalpha-benzoyl-L-arginine ethyl ester as an acyl donor affirmed that Glu-Glu-tri-OEt bound more strongly than Glu-di-OEt both to the S- and S'-subsites of papain. Therefore, what occurred during the initial stage of the polymerization was interpreted as follows: the rate of the papain-catalyzed dimerization of Glu-di-OEt was extremely slow, once Glu-Glu-tri-OEt was initially synthesized it exclusively bound to the active site of papain, and then papain utilized the dimer in polymerization effectively rather than the monomer. |
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Authors:
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Asako Narai-Kanayama; Hiroyuki Koshino; Keiichi Aso |
Publication Detail:
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Type: Journal Article Date: 2008-03-20 |
Journal Detail:
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Title: Biochimica et biophysica acta Volume: 1780 ISSN: 0006-3002 ISO Abbreviation: Biochim. Biophys. Acta Publication Date: 2008 Jun |
Date Detail:
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Created Date: 2008-05-16 Completed Date: 2008-07-31 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0217513 Medline TA: Biochim Biophys Acta Country: Netherlands |
Other Details:
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Languages: eng Pagination: 881-91 Citation Subset: IM |
Affiliation:
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Faculty of Applied Life Science, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo 180-8602, Japan. a-narai@nvlu.ac.jp |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Catalysis Glutamates / chemistry* Hot Temperature Kinetics Mass Spectrometry Models, Chemical* Papain / chemistry* Polyesters / chemical synthesis*, chemistry |
| Chemical | |
Reg. No./Substance:
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0/Glutamates; 0/Polyesters; 16450-41-2/glutamic acid diethyl ester; EC 3.4.22.2/Papain |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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