Carballo J, Bernardo A, Prieto M J, Sarmiento R M
Laboratorio de Lactologia e Industrias Làcteas, Facultad de Veterinaria, Universidad de Leòn, Spain.
Ital J Biochem. 1993 Mar-Apr;42(2):79-89.
L-glycol dehydrogenase from Enterobacter aerogenes shows a high affinity by NADH (Ks = 2-4 microM; Km = 4.3-9.7 microM), which indicates that it must operate in vivo saturated with this coenzyme. Michaelis and dissociation constants for the reduction of the carbonyl substrates assayed (diacetyl, 2,3-pentanedione, methylglyoxal and ethyl pyruvate) are similar to those reported for other diacetyl reducing enzymes. The kinetic mechanism followed by these reactions has also been studied. Our results prove that the reduction of diacetyl and ethyl pyruvate takes place via an Ordered Bi-Bi system with the coenzyme as the leading substrate. Methylglyoxal and 2,3-pentanedione are reduced by the same mechanism or by a Theorell-Chance one.
产气肠杆菌的L-甘油脱氢酶对NADH具有高亲和力（Ks = 2-4 microM；Km = 4.3-9.7 microM），这表明它在体内一定是在该辅酶饱和的状态下发挥作用。所测定的羰基底物（双乙酰、2,3-戊二酮、甲基乙二醛和丙酮酸乙酯）还原反应的米氏常数和解离常数与其他双乙酰还原酶所报道的相似。还研究了这些反应所遵循的动力学机制。我们的结果证明，双乙酰和丙酮酸乙酯的还原是通过以辅酶作为主要底物的有序双底物双产物系统进行的。甲基乙二醛和2,3-戊二酮通过相同的机制或通过Theorell-Chance机制被还原。
