title: The conversion of L-cystathionine into the cyclic ketimine form by heated rat liver extracts containing cystathionase and transaminase activities.
abstract: Rat liver homogenates heated for 10 min at 60 degrees C incubated with L-cystathionine yield cystathionine ketimine which was identified by its typical UV spectrum and by cochromatography with authentic samples on the amino acid analyzer. Alanine and alpha-amino butyric acid have been also detected among the final products. The reaction is due to heat stable gamma-cystathionase and transaminases present in the extracts. Cystathionase produces alpha-keto butyric acid and pyruvic acid which are then used for the transamination of the remaining cystathionine to yield the ketimine. This is the first report indicating the occurrence in a mammalian tissue of an enzymatic system using cystathionine for reactions differing from the traditional transulfuration to cysteine.
mesh_terms: D000818:Animals; D003540:Cystathionine / Q000031:analogs & derivatives / Q000378:metabolism*; D003542:Cystathionine gamma-Lyase / Q000378:metabolism*; D006358:Hot Temperature; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008190:Lyases / Q000378:metabolism*; D000637:Transaminases / Q000378:metabolism*
chemical_list: D003540:Cystathionine; C038681:cystathionine ketimine; D000637:Transaminases; D008190:Lyases; D003542:Cystathionine gamma-Lyase