Energy-linked pyridine nucleotide transhydrogenase activity in photosynthetically grown Rhodopseudomonas palustris.
Rhodopseudomonas palustris (ATCC 17001) develops energy-dependent NADP+ transhydrogenase activity while growing photosynthetically on thiosulfate, formate, or acetate as the electron donors. The enzymatic activity is present in the supernatant fraction S-144 000. -- As reported, this fraction contains small membrane fragments but no closed vesicles and was shown to drive energy-dependent reversed electron flow as well as an aerobic respiratory electron transport. The energy-dependent transhydrogenase reaction in this fraction can be driven either by ATP, ADP, or inorganic pyrophosphate, but also by acetyl phosphate or acetyl-coenzyme A in the presence of orthophosphate. -- Arsenate acts as an inhibitor and decreases preferentially the acetyl-coenzyme A-dependent and the acetyl phosphate-driven reaction; whereas, oligomycin inhibits preferentially the ATP- and the acetyl phosphate-dependent reactions. -- Acetate kinase and a phosphotransacetylase are operative in S-144 000.
D000085:Acetates / Q000494:pharmacology; D000105:Acetyl Coenzyme A / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000693:Anaerobiosis; D001149:Arsenates / Q000494:pharmacology; D011756:Diphosphates / Q000494:pharmacology; D008027:Light; D008274:Magnesium / Q000494:pharmacology; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D009840:Oligomycins / Q000494:pharmacology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010101:Oxygen Consumption; D010788:Photosynthesis; D012241:Rhodopseudomonas / Q000187:drug effects / Q000201:enzymology*
D000085:Acetates; D001149:Arsenates; D011756:Diphosphates; D009840:Oligomycins; D009943:Organophosphorus Compounds; D009243:NAD; D009249:NADP; D000105:Acetyl Coenzyme A; D000255:Adenosine Triphosphate; D009247:NADH, NADPH Oxidoreductases; D008274:Magnesium