乳酸氧化酶研究进展

Research Progress on Lactate Oxidase

乳酸氧化酶能够氧化乳酸生成丙酮酸 ,由于反应过程中不需要外源辅酶作为电子受体 ,而具有较好的应用前景。乳酸氧化酶和许多黄素蛋白酶相比较 ,具有明显的共性 ,因此可视为黄素蛋白家族中的一员。乳酸单加氧酶的催化机理和乳酸氧化酶相似 ,但产物不同 ,这主要是由于中间产物复合体稳定性的差别。乳酸单加氧酶催化形成的中间复合体EFMNH2 pyruvate很稳定 ,在氧的作用下 ,生成EFMN pyruvate H2 O2 中间体 ,继续反应形成乙酸 ,CO2 和H2 O ;乳酸氧化酶生成的EFMNH2 pyruvate复合体不稳定 ,丙酮酸很快从复合体上分离下来 ,还原型中间体EFMNH2 被氧氧化 ,同时形成过氧化氢。

Lactate oxidase catalyzed the direct formation of pyruvate from lactate without requiring NAD + or NADP + as cofactor,which brings it a bright application prospects. Considerable evident had been accumulated that the enzyme was a member of the family of FMN-containing enzymes that catalyzed the oxidation of α-hydroxyacids.Catalysis mechanism of the enzyme had been studied and found to share many characteristics with those of lactate monooxygenase,but differ on product.These differences arise from different stabilities of a common intermediate of reduced flavin enzyme and pyruvate.In the case of the monooxygenase this complex is very stable and is the form that reacts with O 2 to give a complex in which the oxidative decarboxylation occurs,yielding the products,acetate,CO 2,and H 2O.With lactate oxidase,the complex dissociates rapidly,with the result of the free reduced flavin formed enzyme reacts with O 2,to give the observed products,pyruvate and H 2O 2.;