Analyzes of Structure and Function of Novel Carbonyl Metabolic Enzymes : MALDO and MALCO

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Three P450 isozymes, named P450MDX-A,P450GPF-A and P450JM-C,which are major isozymes responsible for 9-anthraldehyde microsomal aldehyde oxygenase (MALDO) activity were purified from hepatic microsomes of mice, guinea pigs and Japanese monkeys. The N-terminal amino acid sequences of these isozymes suggest that the isozymes are member of CYP2B subfamily. Piperonal, alpha-n-amylcinnamaldehyde, vanillin and tolaldehyde were also oxidized to the corresponding carboxylic acids by MALDO of mouse liver.Three P450 isozymes, named P450MDX-B,P450GPF-B and P450JM-E,which are major isozymes responsible for 7-OH-DELTA^8-tetrahydrocannabinol microsomal alcohol oxygenase (MALCO) activity were purified from hepatic microsomes of mice, guinea pigs and female Japanese monkeys. The N-terminal amino acid sequences of these isozymes suggest that the isozymes are member of CYP3A subfamily.A cDNA encoding a P450 isozyme was isolated from a cDNA library constructed from male 129 mouse liver. The cDNA,designated Cyp2c-29 (129), may correspond to a polymorphic variant of Cyp2c-29 (isolated from C57BL/6 mouse liver cDNA library). One out of the six nucleotide changes is nonconservative, resulting in the replacement of 106 Ile of Cyp2c-29 (C57BL/6) by 104 Met. The comparison with Cyp2c-29 sequence shows 4 differences concentrated within a 174-nucleotide sequence located 228-405. mRNAs corresponding to this region (188-445) in C57BL/6, ddN,ddY,C3H,DBA/2 and ICR mouse livers were amplified by the methods of RT-PCR.The amplified nucleotide sequences were the identical with those of Cyp2c-29 (129) except for C57BL/6. A cDNA clone encoding P450MDX-B was isolated from a mouse liver cDNA library. The nucleotide sequence of the cDNA is identical to that of Cyp3a-11.