title: Involvement of cystathionase in the formation of alkane-thiols from corresponding cysteine conjugates.
abstract: 1. Rat liver cystathionase [EC.4.4.1.1] mediated a cleavage reaction of the C-S bond of S-alkyl-L-cysteine conjugates to give equimolar amounts of corresponding thiols, ammonia, and pyruvic acid. Neither S-aryl- nor S-aralkyl-L-cysteine conjugates were acceptable substrates. 2. The Km value for S-(tert-butyl)-L-cysteine was 0.3 mM at pH 8.5 in Tris-HCl buffer. 3. The S-alkyl-L-cysteine lyase activity of cystathionase was inhibited with carbonyl reagents and dithiothreitol. 4. The present finding that cystathionase has activity towards cysteine conjugates may provide some insights into the role of this enzyme in the metabolism of xenobiotics.
authors.affiliation: Nippon Roche Research Center, Kanagawa Pref., Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tomisawa
authors.forename: N
authors.initials: N
authors.lastname: Ichimoto
authors.forename: S
authors.initials: S
authors.lastname: Ichihara
authors.forename: H
authors.initials: H
authors.lastname: Fukazawa
authors.forename: M
authors.initials: M
authors.lastname: Tateishi
mesh_terms: D000473:Alkanes / Q000378:metabolism; D000818:Animals; D002845:Chromatography; D002850:Chromatography, Gel; D003542:Cystathionine gamma-Lyase / Q000302:isolation & purification / Q000378:metabolism*; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D017886:Durapatite; D006882:Hydroxyapatites; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008190:Lyases / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D000473:Alkanes; D006882:Hydroxyapatites; D017886:Durapatite; D008190:Lyases; D003542:Cystathionine gamma-Lyase; D003545:Cysteine