title: Metabolism of 2,5-diphenyloxazole (PPO) by trout liver microsomal mixed function monooxygenase.
abstract: Metabolism of 2,5-diphenyloxazole (PPO) has been characterized in trout liver microsomes. Trout liver microsomes have been found to metabolize PPO into at least one NaOH extractable flourescing metabolite having a strong excitation peak at 345 nm and an emission peak at about 510 nm. As the metabolite(s) has (have) not been characterized, Vmax has not been determined, however in arbitary fluorescent units (FU) Vmax is several fold higher in the trout than in the male rat hepatic microsomes. Km is 12.7 M, being about twice as high as reported for mouse (Cantrell et al. 1975). Optimum assay conditions have been established for the metabolism of PPO by trout liver microsomes. NADPH generating system is essential and the metabolism was strongly inhibited by alpha-naphthoflavone, but much less markedly by SKF 525 A or metyrapone.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008797:Metyrapone / Q000494:pharmacology; D008862:Microsomes, Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010080:Oxazoles / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D011335:Proadifen / Q000494:pharmacology; D051381:Rats; D012487:Salmonidae / Q000378:metabolism*; D013045:Species Specificity; D013050:Spectrometry, Fluorescence; D014337:Trout / Q000378:metabolism*
chemical_list: D003580:Cytochromes; D005419:Flavonoids; D010080:Oxazoles; C009012:2,5-diphenyloxazole; D011335:Proadifen; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D001189:Aryl Hydrocarbon Hydroxylases; D008797:Metyrapone