Arthrobacter K1108乙内酰脲酶反应条件和立体选择性研究

研究了Arthrobacter K1108乙内酰脲酶的反应条件，结果表明，K1108乙内酰脲酶的最适反应温度为55℃，最适pH为7.0,Co^2 和Fe^2 对该酶有激活作用，而Ca^2 有严重抑制作用。K1108乙内酰脲酶的底物专一性较强，其最适底物为5－苄基乙内酰脲，5－苯基乙内酰脲和5－吲哚甲基乙内酰脲均不能作为其有效底物。对K1108乙内酰脲酶立体反应机制研究结果表明，其乙内酰脲水解酶不具立体选择性，决定产物立体构型的酶是N－氨甲酰氨基酸水解酶。

Studies on Bioconversion Conditions and Stereoselectivity of Arthrobacter K1108 Hydantoinase

The bioconversion conditions of hydantoinase of Arthrobacter K1108 were studied. It was shown that the optimum temperature of the enzyme is 55 degrees C, and the optimum pH is 7.0. The enzyme can be activated by Co2+ and Fe2+, while inhibited by Ca2+. The optimal substrate of the hydantoinase is 5-benzylhydantoin, while 5-phenylhydantoin and 5-indolylmethylhydantoin cannot effectively digested, showing a high specificity on the substrates. An investigation on the hydantoinase stereoselectivity mechanism showed that the N-carbamoylamino acid hydrolase is stereoselective but the hydantoin hydrolase is not.