利用具有缬氨酸转氨酶活性的工程菌对DL-缬氨酸进行拆分,考察了反应温度、pH值、底物摩尔比、底物浓度和金属离子对酶活性和底物转化率的影响。结果显示,该催化反应的最适反应条件为:反应温度是45℃,pH=9,L-缬氨酸与丙酮酸的摩尔比1∶8,DL-缬氨酸初始浓度为0.6 mol/L、丙酮酸初始浓度为2.4 mol/L,0.5 mmol/L的Mg2+和Na+对酶活性有明显的促进作用。

An engineered strain with catalytic activity of valine-pyruvate transaminase was used in chiral resolution of DL-valine.The effect of reaction conditions such as reaction temperature,pH,substrate mole ratio,substrate concentration and metal ions on enzyme activity was studied.Results showed that the optimal conditions were 45℃ and pH9.The optimal substrate ratio of L-valine to pyruvic acid was 1∶ 8(mol∶ mol).The initial substrate concentration of DL-valine and pyruvic acid were 0.6 mol/L and 2.4 mol/L respectively.Enzyme activity was improved by addition of 0.5 mmol/L Mg2+ and Na+.