Walker D J, Fioravanti C F
Department of Biological Sciences, Bowling Green State University, Ohio 43403, USA.
J Parasitol. 1995 Jun;81(3):350-3.
Adult Hymenolepis diminuta mitochondria catalyze a transhydrogenation reaction between NADPH and NAD and between NADH and NAD. The NADPH-->NAD reaction is catalyzed by an inner membrane-associated pyridine nucleotide transhydrogenase, whereas the NADH-->NAD reaction is ostensibly catalyzed by another system(s). The source(s) of NADH-->NAD activity was evaluated by assessments of its intramitochondrial distribution and thermal lability and by comparisons with the distribution/thermal lability of NADH dehydrogenase, lipoamide dehydrogenase, and NADPH-->NAD transhydrogenase. The occurrence of NADH and lipoamide dehydrogenase components was readily demonstrable. Like NADPH-->NAD transhydrogenase, NADH dehydrogenase was essentially membrane bound. Lipoamide dehydrogenase and NADH-->NAD activities were, at different levels, in the membrane and soluble fractions. Based on thermal profiles, NADH and lipoamide dehydrogenase differed from each other and from NADPH-->NAD transhydrogenase. Although the NADH-->NAD profile closely paralleled that for lipoamide dehydrogenase, it also was similar to the NADH dehydrogenase profile. Collectively, these data are consistent with the supposition that the H. diminuta mitochondrial NADH-->NAD transhydrogenation reaction is catalyzed by lipoamide dehydrogenase and possibly by NADH dehydrogenase rather than by an independent transhydrogenase system.
成年微小膜壳绦虫线粒体催化NADPH与NAD之间以及NADH与NAD之间的转氢反应。NADPH→NAD反应由内膜相关的吡啶核苷酸转氢酶催化，而NADH→NAD反应表面上由另一个系统催化。通过评估其线粒体内分布和热稳定性，并与NADH脱氢酶、硫辛酰胺脱氢酶和NADPH→NAD转氢酶的分布/热稳定性进行比较，来评估NADH→NAD活性的来源。NADH和硫辛酰胺脱氢酶成分的存在很容易证明。与NADPH→NAD转氢酶一样，NADH脱氢酶基本上与膜结合。硫辛酰胺脱氢酶和NADH→NAD活性在不同程度上存在于膜和可溶性部分中。根据热谱图，NADH和硫辛酰胺脱氢酶彼此不同，也与NADPH→NAD转氢酶不同。尽管NADH→NAD谱图与硫辛酰胺脱氢酶的谱图非常相似，但它也与NADH脱氢酶的谱图相似。总体而言，这些数据与以下假设一致，即微小膜壳绦虫线粒体NADH→NAD转氢反应由硫辛酰胺脱氢酶催化，可能也由NADH脱氢酶催化，而不是由独立的转氢酶系统催化。
