Chen S, Guillory R J
Biochem Biophys Res Commun. 1985 Jun 14;129(2):584-90. doi: 10.1016/0006-291x(85)90191-3.
The purified mitochondrial NADH dehydrogenase enzyme has been shown to catalyze a rapid [4B-3H] NADH-H2O exchange reaction. When the enzyme is subjected to a single freeze-thaw cycle there is a complete loss of NADH dehydrogenation without a measurable decrease in the [4B-3H] NADH-H2O exchange. Complete loss of the [4B-3H] NADH-H2O exchange follows brief exposure to ultraviolet photoirradiation. The differential sensitivity of the water exchange reaction and the dehydrogenase activity suggests a direct involvement of the enzymes flavin cofactor in the catalysis of the [4B-3H] NADH-H2O exchange. Arylazido-beta-alanyl NAD+ (A3'-0-[3-[N-4-azido-2-nitrophenyl)amino] propionyl]NAD+) is shown to be a potent photodependent inhibitor of the [4B-3H] NADH-H2O exchange activity following photoirradiation with visible light. This is consistent with the observed photodependent inhibition of the dehydrogenase activity by this photoprobe (Chen, S. and Guillory, R.J. (1981) J. Biol. Chem. 256, 8318-8323).
纯化的线粒体NADH脱氢酶已被证明能催化快速的[4B-3H]NADH-H2O交换反应。当该酶经历单次冻融循环时，NADH脱氢作用完全丧失，而[4B-3H]NADH-H2O交换没有可测量的下降。短暂暴露于紫外光照射后，[4B-3H]NADH-H2O交换完全丧失。水交换反应和脱氢酶活性的差异敏感性表明，该酶的黄素辅因子直接参与了[4B-3H]NADH-H2O交换的催化过程。芳基叠氮基-β-丙氨酰NAD+（A3'-0-[3-[N-4-叠氮基-2-硝基苯基）氨基]丙酰基]NAD+）在可见光照射后，被证明是[4B-3H]NADH-H2O交换活性的一种有效的光依赖性抑制剂。这与该光探针观察到的对脱氢酶活性的光依赖性抑制是一致的（Chen，S.和Guillory，R.J.（1981年）《生物化学杂志》256，8318-8323）。
