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B6db references: 86118386

type Journal Article
authors Larsen, G. L.; Stevens, J. L.
title Cysteine conjugate beta-lyase in the gastrointestinal bacterium Eubacterium limosum
journal Mol Pharmacol
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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