Document Detail

A thiono-beta-lactam substrate for the beta-lactamase II of Bacillus cereus. Evidence for direct interaction between the essential metal ion and substrate.
MedLine Citation:
PMID:  2499308     Owner:  NLM     Status:  MEDLINE    
An 8-thionocephalosporin was shown to be a substrate of the beta-lactamase II of Bacillus cereus, a zinc metalloenzyme. Although it is a poorer substrate, as judged by the Kcat./Km parameter, than the corresponding 8-oxocephalosporin, the discrimination against sulphur decreased when the bivalent metal ion in the enzyme active site was varied in the order Mn2+ (the manganese enzyme catalysed the hydrolysis of the oxo compound but not that of the thiono compound), Zn2+, Co2+ and Cd2+. This result is taken as evidence for kinetically significant direct contact between the active-site metal ion of beta-lactamase II and the beta-lactam carbonyl heteroatom. No evidence was obtained, however, for accumulation of an intermediate with such co-ordination present.
B P Murphy; R F Pratt
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Biochemical journal     Volume:  258     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1989 Mar 
Date Detail:
Created Date:  1989-06-27     Completed Date:  1989-06-27     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  765-8     Citation Subset:  IM    
Department of Chemistry, Wesleyan University, Middletown, CT 06457.
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MeSH Terms
Bacillus cereus / enzymology*
Binding Sites
Cadmium / metabolism
Cephalosporinase / metabolism*
Cephalosporins / metabolism*
Cobalt / metabolism
Manganese / metabolism
Sulfhydryl Compounds / metabolism
Zinc / metabolism
beta-Lactamases / metabolism*
Reg. No./Substance:
0/Cephalosporins; 0/Sulfhydryl Compounds; 7439-96-5/Manganese; 7440-43-9/Cadmium; 7440-48-4/Cobalt; 7440-66-6/Zinc; EC 3.5.2.-/Cephalosporinase; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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