Crystalline 3-methylaspartase from a facultative anaerobe, Escherichia coli strain YG1002.

Crystalline 3-methylaspartase (EC 4.3.1.2) from Escherichia coli strain YG1002 that had been isolated from soil was characterized. The enzyme activity was induced when the organism was grown statically on medium containing (S)-glutamic acid. Its molecular mass is about 84 kDa, and it may be composed of two identical subunits of 42 kDa. The enzyme requires both divalent and monovalent cations such as Mg2+ and K+, respectively. The enzyme catalyzes reversible amination-deamination between mesaconic acid and (2S,3S)-methylaspartic acid, which is the best substrate.