title: Photoaffinity labelling of mitochondrial NADH dehydrogenase with arylazidoamorphigenin, an analogue of rotenone.
abstract: A photoaffinity-labelling analogue of the respiratory inhibitor rotenone was synthesized from the naturally occurring rotenoid amorphigenin. The analogue inhibits NADH-ubiquinone oxidoreductase activity at concentrations comparable with those of rotenone. Photolysis of the radiolabelled analogue bound to isolated NADH-ubiquinone oxidoreductase resulted in preferential incorporation of radioactivity into a polypeptide of Mr 33 000, particularly at low concentrations of the inhibitor. Preparations of the enzyme differ in a parallel fashion in the content of this polypeptide, the degree of photolabelling by the analogue and their sensitivity to rotenone, providing further evidence that the 33 000-Mr protein forms part of the rotenone-binding site.
mesh_terms: D000345:Affinity Labels / Q000138:chemical synthesis; D000818:Animals; D001386:Azides / Q000138:chemical synthesis; D002417:Cattle; D003579:Cytochrome Reductases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D046911:Macromolecular Substances; D008929:Mitochondria, Heart / Q000201:enzymology*; D009245:NADH Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012402:Rotenone / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000345:Affinity Labels; D001386:Azides; D046911:Macromolecular Substances; D012402:Rotenone; D003579:Cytochrome Reductases; D009245:NADH Dehydrogenase