title: Aflatoxin inhibition of rat liver mitochondrial cytochrome oxidase activity.
abstract: Aflatoxins B1, B2, G1, G2, and M1 have been evaluated for activity toward cytochrome oxidase in isolated rat liver mitochondria employing ferrocytochrome c and p-phenylene diamine as reductants. The aflatoxins inhibited the cytochrome oxidase activity to a greater extent when monitored by O2 uptake measurements than by substrate oxidation. AFG2 and AFM1 were the most potent (50-70%). Using oligomycin and 2,4-DNP as respiratory inhibitor and uncoupler, respectively, the aflatoxins appear to inhibit e- rather than energy transfer reactions. These toxins did not uncouple cytochrome oxidase activity.
mesh_terms: D000348:Aflatoxins / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors*; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
chemical_list: D000348:Aflatoxins; D003576:Electron Transport Complex IV