title: Substitution of S-(beta-aminoethyl)-cysteine for active-site lysine of thermostable aspartate aminotransferase.
abstract: The active site lysyl residue (K239) of the thermostable aspartate aminotransferase [EC 2.6.1.1] was replaced by cysteinyl residue by means of site-directed mutagenesis. The K239C mutant enzyme obtained was catalytically inactive. The reaction of the cysteinyl residue of the K239C mutant enzyme with ethylenimine led to the formation of S-(beta-aminoethylcysteinyl (SAEC) residue. The K239SAEC mutant enzyme obtained showed about 25% of the activity of wild-type enzyme, and absorbed at 375 nm, which suggested the internal Schiff base formation.
authors: Laboratory of Microbial Biochemistry, Kyoto University.
authors: T
authors: T
authors: Yoshimura
authors: Y
authors: Y
authors: Matsushima
authors: K
authors: K
authors: Tanizawa
authors: M H
authors: MH
authors: Sung
authors: T
authors: T
authors: Yamauchi
authors: M
authors: M
authors: Wakayama
authors: N
authors: N
authors: Esaki
authors: K
authors: K
authors: Soda
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001219:Aspartate Aminotransferases / Q000235:genetics*; D001388:Aziridines / Q000494:pharmacology; D001407:Bacillus / Q000201:enzymology; D001665:Binding Sites / Q000187:drug effects; D003545:Cysteine / Q000031:analogs & derivatives* / Q000235:genetics; D008239:Lysine / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D013053:Spectrophotometry
chemical_list: D000596:Amino Acids; D001388:Aziridines; C000204:S-2-aminoethyl cysteine; C033132:aziridine; D001219:Aspartate Aminotransferases; D008239:Lysine; D003545:Cysteine