|
type |
Journal Article |
authors |
Larsen, G. L.; Stevens, J. L. |
title |
Cysteine conjugate beta-lyase in the gastrointestinal bacterium Eubacterium limosum |
journal |
Mol Pharmacol |
Activity |
4.4.1.13 |
ui |
86118386 |
year |
(1986) |
volume |
29 |
number |
1 |
pages |
97-103. |
| |
keywords |
Animal |
abstract |
A cysteine conjugate beta-lyase (beta-lyase) from the gastrointestinal bacterium Eubacterium limosum has been isolated and characterized. This organism has the highest specific activity for cysteine conjugate beta- lyase of the gastrointestinal bacteria studied. The beta-lyase was found to cleave the thioether linkage of S-alkyl- and S-aryl-L-cysteine conjugates. Stoichiometric amounts of 2-mercaptobenzothiazole, pyruvic acid, and ammonia were produced from the beta-lyase cleavage of S-(2- benzothiazolyl)-L-cysteine. The enzyme activity was inhibited by hydroxylamine, iodoacetic acid, or KCN. The enzyme appears to be a 75,000-Da dimer of two 38,000-Da subunits. A natural substrate, cystathionine, was cleaved by this enzyme, indicating that this beta- lyase has beta-cystathionase activity. These data suggest that a beta- cystathionase from E. limosum may be an important enzyme in the metabolism of a wide range of cysteine conjugates of xenobiotics to thiol-containing products. |
last changed |
2002/11/12 16:17 |
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