Fioravanti C F, McKelvey J R, Reisig J M
Department of Biological Sciences, Bowling Green State University, Ohio 43403-0212.
J Parasitol. 1992 Oct;78(5):774-8.
Employing "phosphorylating" submitochondrial particles as the source of pyridine nucleotide transhydrogenase, the occurrence of an energy-linked NADH----NADP+ transhydrogenation in the adult cestode Hymenolepis diminuta was demonstrated. The isolated particles displayed rotenone-sensitive NADH utilization and the reversible transhydrogenase, with the NADPH----NAD+ transhydrogenation being more prominent. Although not inhibiting the NADPH----NAD+ reaction, rotenone, but not oligomycin, inhibited the catalysis of NADH----NADP+ transhydrogenation. In the presence of rotenone, Mg2+ plus ATP stimulated by more than 3-fold NADH----NADP+ transhydrogenation. This stimulation was ATP specific and was abolished by EDTA or oligomycin. Succinate was essentially without effect on the NADH----NADP+ reaction. These data demonstrate the occurrence of an energy-linked transhydrogenation between NADH and NADP+ with energization resulting from either electron transport-dependent NADH oxidation or ATP utilization via the phosphorylating mechanism in accord with the preparation of "phosphorylating" particles. This is the first demonstration of an energy-linked transhydrogenation in the parasitic helminths and apparently in the invertebrates generally.
利用“磷酸化”亚线粒体颗粒作为吡啶核苷酸转氢酶的来源，证实了成年绦虫微小膜壳绦虫中存在能量偶联的NADH----NADP +转氢作用。分离出的颗粒表现出对鱼藤酮敏感的NADH利用和可逆的转氢酶，其中NADPH----NAD +转氢作用更为显著。鱼藤酮虽然不抑制NADPH----NAD +反应，但能抑制NADH----NADP +转氢作用的催化，而寡霉素则无此作用。在鱼藤酮存在的情况下，Mg2 +加ATP能使NADH----NADP +转氢作用增强3倍以上。这种刺激具有ATP特异性，可被EDTA或寡霉素消除。琥珀酸对NADH----NADP +反应基本无影响。这些数据表明，在NADH和NADP +之间存在能量偶联的转氢作用，其能量来源于电子传递依赖的NADH氧化或通过磷酸化机制的ATP利用，这与“磷酸化”颗粒的制备情况一致。这是首次在寄生蠕虫中，显然也是在一般无脊椎动物中证明能量偶联的转氢作用。
