Mechanism of transfer of reduced nicotinamide adenine dinucleotide among dehydrogenases.
Mechanism of transfer of reduced nicotinamide adenine dinucleotide among dehydrogenases.
复制标题
还原型烟酰胺腺嘌呤二核苷酸在脱氢酶之间的转移机制。
DOI：
10.1021/bi00324a013
复制
发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
Bernhard,SA
中科院分区：
文献类型：
--
作者：
Srivastava,DK;Bernhard,SA
俄勒冈州大学分子生物学研究所，尤金，俄勒冈州97403接收于1984年4月16日摘要：通过研究E2催化的NADH还原S2，研究了NADH从一种脱氢酶（E1）转移到另一种脱氢酶（E2）的途径。实验条件是Et的浓度超过NADH的浓度，而NADH的浓度又比E2大得多;因此，游离（含水）NADH的浓度极低。因此，如果E2催化的反应需要无配体的NADH水溶液，则S2的还原速率将非常慢。我们对八种辅酶的结果与NADH在E1和E2之间的直接转移完全一致，只要这两种酶通过烟酰胺环的相对面（A和B）转移氢。当两种酶都是A或都是B时，仅通过水性溶剂发生NADH转移。一些机械推论及其可能的生理意义进行了讨论。
Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 Received April 16, 1984 abstract: The pathway for the transfer of NADH from one dehydrogenase (EJ to another dehydrogenase (E2) has been investigated by studying the E2-catalyzed reduction of S2 by NADH. The experimental conditions are that the concentration of Et exceeds that of NADH, which in turn is very much greater than E2; hence, the concentration of free (aqueous) NADH is exceedingly low. The rate of reduction of S2 will hence be very slow if unliganded aqueous NADH is required for the E2-catalyzed reaction. Our results with eight dehydrogenases are entirely consistent with the direct transfer of NADH between E (and E2 whenever the two enzymes transfer hydrogen via opposite faces (A and B) of the nicotinamide ring. Whenever the two enzymes are both A or both B, NADH transfer occurs only via the aqueous solvent. Some mechanistic inferences and their possible physiological significance are discussed.