Microsomal aldehyde oxygenase (MALDO): purification and characterization of a cytochrome P450 isozyme responsible for oxidation of 9-anthraldehyde to 9-anthracenecarboxylic acid in monkey liver.
Oxidative activity of 9-anthraldehyde (9-AA) to 9-anthracenecarboxylic acid in monkey liver was mainly located in microsomes. The reaction required NADPH as an essential cofactor and was significantly inhibited by SKF 525-A, metyrapone, disulfiram, and CO, potent inhibitors of microsomal aldehyde oxygenase (MALDO). Two cytochrome P450 isozymes, named P450JM-A and P450JM-C, which mediate the oxidative biotransformation of 9-AA were purified from hepatic microsomes of untreated male and female Japanese monkeys, respectively. These isozymes each showed a single band of molecular mass 51,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The NH2-terminal amino acid sequences of P450JM-A and P450JM-C are highly homologous with those of several P450s belonging to the CYP2A and CYP2B subfamilies, respectively. The anti-P450JM-C antibody significantly suppressed 9-AA MALDO activity in monkey liver, but anti-P450JM-A antibody did not. The antibody against CYP2C11, which is a major isozyme responsible for 9-AA MALDO in male rat liver, also inhibited the activity. These results indicate that P450JM-C and isozyme(s) immunologically related to CYP2C11 predominantly possess MALDO activity toward 9-AA.
Matsunaga
T
T
Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa.
Iwawaki
Y
Y
Watanabe
K
K
Yamamoto
I
I
Kageyama
T
T
Yoshimura
H
H
D000595:Amino Acid Sequence; D000818:Animals; D000873:Anthracenes / Q000378:metabolism*; D001189:Aryl Hydrocarbon Hydroxylases; D065637:Cytochrome P-450 CYP2A6; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008251:Macaca; D008253:Macaca mulatta; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
D000873:Anthracenes; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D009243:NAD; D009249:NADP; C073050:9-anthraldehyde; C010030:9-anthroic acid; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D010105:Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C086292:Cyp2c29 protein, mouse; D065637:Cytochrome P-450 CYP2A6; D000072467:Cytochrome P450 Family 2