type	Journal Article
authors	Larsen, G. L.; Larson, J. D.; Gustafsson, J. A.
title	Cysteine conjugate beta-lyase in the gastrointestinal bacterium Fusobacterium necrophorum
journal	Xenobiotica
Activity	4.4.1.13
ui	84174452
year	(1983)
volume	13
number	11
pages	689-700.
keywords	Fusobacterium necrophorum/*enzymology
abstract	A cysteine conjugate beta-lyase from the anaerobic gastrointestinal bacterium Fusobacterium necrophorum was purified 51-fold by heat treatment, ammonium sulphate fractionation, gel-filtration chromatography, and anion-exchange chromatography. This enzyme catalyses the cleavage of the thioether linkage in cysteine conjugates of the following S-alkyl- or S-aryl-linked compounds: cysteine conjugate of propachlor (2-S-cysteinyl-N-isopropylacetanilide); 1,2- dihydro-1-hydroxy-2-S-cysteinylnaphthalene and S-(2- benzothiazolyl)cysteine. 2-Mercapto-N-isopropylacetanilide, pyruvic acid and ammonia were produced from the beta-lyase cleavage of the cysteine conjugate of propachlor in equimolar ratios. The apparent Km values for the cysteine conjugate of propachlor and S- (benzothiazolyl)cysteine were 1.1 and 1.0 mM, respectively. Pyridoxal phosphate was required for enzymic activity. Ammonium ion activated enzymic activity, while hydroxylamine completely inhibited the enzyme. Dithiothreitol and bovine serum albumin had no effect on enzymic activity.
last changed	2002/11/12 16:17