title: Purification and characterization of S-alkylcysteine alpha,beta-lyase from Pseudomonas putida.
abstract: S-Alkylcysteine alpha,beta-lyase [EC 4.4.1.6] was purified to more than 90% homogeneity from the cell extract of Pseudomonas putida ICR 3640. The enzyme has a molecular weight of about 195,000, and is composed of six subunits identical in molecular weight (37,000). Pyridoxal 5'-phosphate is required as a cofactor. The enzyme catalyzes the alpha,beta-elimination of S-methyl-L-cysteine and its analogs such as S-ethyl-L-cysteine, L-djenkolate, Se-methyl-DL-selenocysteine, and O-methyl-L-serine. However, S-methyl-D-cysteine, L-methionine, and L-norvaline were inert. The enzyme catalyzes also the beta-replacement reaction of the thiomethyl group of S-methyl-L-cysteine with various thiols to yield the corresponding S-substituted cysteines. In addition to S-methyl-L-cysteine, Se-methyl-DL-selenocysteine and O-methyl-L-serine also serve as substrates in the beta-replacement reaction.
authors.affiliation: Institute for Chemical Research, Kyoto University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kamitani
authors.forename: N
authors.initials: N
authors.lastname: Esaki
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Imahara
authors.forename: K
authors.initials: K
authors.lastname: Soda
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D013437:Carbon-Sulfur Lyases; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D008190:Lyases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D011549:Pseudomonas / Q000201:enzymology* / Q000254:growth & development; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D003470:Culture Media; D008190:Lyases; D013437:Carbon-Sulfur Lyases; C019969:S-alkylcysteine lyase