PURIFICATION AND CHARACTERIZATION OF DEXAMETHASONE INDUCIBLE HEPATIC CYTOCHROME-P450 ISOZYMES FROM RHESUS-MONKEY

Two isozymes of hepatic cytochrome P450 named DEX M-1 and M-2 have bee n purified and characterized from dexamethasone (DEX) pretreated (150 mg Kg(-1) body wt x 4 days) rhesus monkeys by various chromatographic procedures. These isozymes demonstrated similar peptide maps. Their ab solute and CO-dithionite reduced difference spectra demonstrated maxim um absorbance at 417 and 449.4 nm, respectively. DEX M-1 and M-2 demon strated polypeptide molecular wt of 50 and 52.5 KDa, specific content of 16.35 and 11.39 nmol mg(-1) protein and 11 and 8 fold purification, respectively. The antibodies against these isozymes cross reacted wit h each other and also demonstrated slight differences in the immunoinh ibition of erythromycin N-demethylase. These results demonstrated that DEX induced two different isozymes of hepatic cytochrome P450 in rhes us monkeys.