title: Kynurenine aminotransferase activity in human liver: identity with human hepatic C-S lyase activity and a physiological role for this enzyme.
abstract: The C-S lyase enzymes are responsible for the generation of mutagenic and cytotoxic metabolites via aberrant drug-metabolising pathways in mammalian tissues. We have examined human hepatic cytosolic, mitochondrial and microsomal fractions for evidence of C-S lyase activity. The cytosolic enzyme was purified using fast protein liquid chromatography over FFQ Sepharose, Mono P and Superose 12. An homogeneous protein (monitored by SDS-PAGE) was obtained following purification, and an 11-fold increase in C-S lyase specific activity was observed. The molecular weight of the enzyme was found to be 37 kDa in denaturing conditions, 82.3 kDa in non-denaturing conditions, and the C-S lyase activity was shown to co-purify with kynurenine aminotransferase activity when the transaminase activity of the enzyme was examined with kynurenine as the substrate.
authors.affiliation: Department of Pharmaceutical Sciences, University of Nottingham, UK.
authors.forename: L D
authors.initials: LD
authors.lastname: Buckberry
authors.forename: I S
authors.initials: IS
authors.lastname: Blagbrough
authors.forename: B W
authors.initials: BW
authors.lastname: Bycroft
authors.forename: P N
authors.initials: PN
authors.lastname: Shaw
mesh_terms: D000328:Adult; D013437:Carbon-Sulfur Lyases; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007526:Isoelectric Point; D008099:Liver / Q000201:enzymology*; D008190:Lyases / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D008970:Molecular Weight; D011247:Pregnancy; D012967:Sodium Dodecyl Sulfate; D000637:Transaminases / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology
chemical_list: D012967:Sodium Dodecyl Sulfate; C039961:S-(1,2-dichlorovinyl)cysteine; D000637:Transaminases; C427605:glutamine - phenylpyruvate transaminase; C021481:kynurenine-oxoglutarate transaminase; D008190:Lyases; D013437:Carbon-Sulfur Lyases; C019969:S-alkylcysteine lyase; D003545:Cysteine