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N-phenylglucosylamine hydrolysis: A mechanistic probe of β-glucosidase.
MedLine Citation:
PMID:  21435675     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The spontaneous hydrolysis of glycosylamines, where the aglycone is either a primary amine or ammonia, is over a hundred million-times faster than that of O- or S-glycosides. The reason for this (as pointed out by Capon and Connett in 1965) is that, in contrast to the mechanism for O- or S-glycoside hydrolysis, hydrolysis of these N-glycosides (e.g., glc-NHR) involves an endocyclic C-O bond cleavage resulting in formation of an imine (iminium ion) which then reacts with water. Since ring-opening is kinetically favored with glycosylamines, compounds such as phenylglucosylamine can be a useful probes of enzymes that have been suggested to possibly follow this mechanism. With β-glucosidase from sweet almonds, the enzyme is highly efficient in catalyzing the hydrolysis of phenyl glucoside (k(cat)/k(non)∼10(14)) and phenyl thioglucoside (k(cat)/k(non)∼10(10)) while with either the almond or the Aspergillus niger enzyme or with yeast α-glucosidase, there is no detectable catalysis of phenylglucosylamine hydrolysis (k(cat)/k(non)<20). These results are consistent with the generally accepted mechanism involving exocyclic bond cleavage by these enzymes.
Authors:
Ying Na; Hong Shen; Larry D Byers
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-3-22
Journal Detail:
Title:  Bioorganic chemistry     Volume:  -     ISSN:  1090-2120     ISO Abbreviation:  -     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-3-25     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1303703     Medline TA:  Bioorg Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011 Elsevier Inc. All rights reserved.
Affiliation:
Department of Chemistry, Tulane University, New Orleans, LA 70118, United States.
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