Energy-linked mitochondrial pyridine nucleotide transhydrogenase of adult Hymenolepis diminuta.
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.
Fioravanti
C F
CF
Department of Biological Sciences, Bowling Green State University, Ohio 43403-0212.
McKelvey
J R
JR
Reisig
J M
JM
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004579:Electron Transport; D005260:Female; D006865:Hydrogenation; D006926:Hymenolepis / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000378:metabolism; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009249:NADP / Q000378:metabolism*; D009250:NADP Transhydrogenases / Q000187:drug effects / Q000378:metabolism*; D009840:Oligomycins / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D012402:Rotenone / Q000494:pharmacology; D013385:Succinate Dehydrogenase / Q000378:metabolism
D009097:Multienzyme Complexes; D009840:Oligomycins; D012402:Rotenone; D009243:NAD; D009249:NADP; D000255:Adenosine Triphosphate; D013385:Succinate Dehydrogenase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D009250:NADP Transhydrogenases; D008274:Magnesium