Preparation of homogeneous NADPH-cytochrome P-450 reductase from rat hepatoma.
NADPH-cytochrome P-450 reductase was purified to homogeneity from hepatoma 5123t.c.(H) microsomes from phenobarbital and hydrocortisone-treated rats by detergent solubilization and affinity chromatography with an overall 8% recovery. The purified enzyme has a minimum subunit molecular weight of 79 000 and contains one molecule each of FMN and FAD per 79 000 molecular weight. The purified hepatoma cytochrome P-450 reductase catalyzes electron transfer to artificial electron acceptors with Km values similar to those of purified liver reductase. The Km value of the hepatoma reductase for NADPH, 13 microM, is also similar to that of purified liver reductase. The tumor reductase appears immunochemically identical to liver reductase by Ouchterlony double-diffusion analysis and inhibition of activity. Peptide maps of the hepatoma and hepatic enzymes after proteolysis demonstrate the identity of the two proteins.
D000818:Animals; D005486:Flavin Mononucleotide / Q000032:analysis; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D006854:Hydrocortisone / Q000494:pharmacology; D007700:Kinetics; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D008970:Molecular Weight; D009251:NADPH-Ferrihemoprotein Reductase / Q000302:isolation & purification* / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011915:Rats, Inbred BUF
D005182:Flavin-Adenine Dinucleotide; D005486:Flavin Mononucleotide; D009251:NADPH-Ferrihemoprotein Reductase; D006854:Hydrocortisone; D010634:Phenobarbital