title: Insight into the active site of Streptomyces cystathionine gamma-lyase based on the results of studies on its substrate specificity.
abstract: The results of studies on the substrate specificities of elimination and replacement reactions allowed insight into the active and regulatory sites of Streptomyces phaeochromogenes cystathionine gamma-lyase (L-cystathionine cysteine-lyase (deaminating), EC 4.4.1.1). The enzyme has an active site and a regulatory site. The active site consists of two subsites; one recognizes the L-forms of amino acids (L-homoserine and L-moieties of cystathionine isomers) and the other shows affinity for thiol compounds with a carboxyl group. The regulatory site is specific for L-cysteine and has no affinity for ordinary thiol compounds, such as 3-mercaptopropionate and thioglycolate.
mesh_terms: D000495:Allosteric Site; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D003542:Cystathionine gamma-Lyase / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D006714:Homoserine / Q000378:metabolism; D008190:Lyases / Q000378:metabolism*; D051381:Rats; D013237:Stereoisomerism; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D000596:Amino Acids; D005656:Fungal Proteins; D013438:Sulfhydryl Compounds; D006714:Homoserine; D008190:Lyases; D003542:Cystathionine gamma-Lyase