期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1990
卷号：36
期号：4-SupplementI
页码：339-347
DOI：10.3177/jnsv.36.4-SupplementI_339
出版社：Center for Academic Publications Japan
摘要：S -Alkylcysteine α, β-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 α, β-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 β-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 β-replacement reaction.
