Ruenitz P C, Thomas H G
Arch Biochem Biophys. 1985 May 15;239(1):270-2. doi: 10.1016/0003-9861(85)90835-5.
Studies of the rates of aldehyde oxidase-mediated oxidation of iminium ion (I) and its specifically labeled counterpart containing deuterium at the methine and methylene carbons of its seven-membered ring (I-d3), are reported. In separate incubations, the isotope effect (kH/kD) on Vmax was 3.3 and that on Km was 1.5. Co-incubation of equimolar amounts of I and I-d3 with aldehyde oxidase resulted in an isotope effect of 2.2 on product ratio. These results support hydrogen transfer from the methine carbon of the seven-membered ring to the molybdenum center of the enzyme as the rate-determining step in the conversion of I to its lactam metabolite (II).
报道了对亚胺离子（I）及其在七元环的次甲基和亚甲基碳上含有氘的特异性标记类似物（I-d3）的醛氧化酶介导氧化速率的研究。在单独孵育时，对Vmax的同位素效应（kH/kD）为3.3，对Km的同位素效应为1.5。等摩尔量的I和I-d3与醛氧化酶共同孵育，对产物比例的同位素效应为2.2。这些结果支持了从七元环的次甲基碳向酶的钼中心的氢转移是I转化为其内酰胺代谢物（II）的速率决定步骤。
