Topical application of benz(a)anthracene to mouse skin elicited a 2-fold increase in cytochrome P-450 content, with accompanying increases in monooxygenase activities such as benzo(a)pyrene hydroxylation, 7-ethoxycoumarin 0-deethylation, and acetanilide 4-hydroxylation, in the microsomes. A major form of cytochrome P-450 was purified from skin microsomes of mice treated with polycyclic aromatic hydrocarbon. A specific content of 1.95 nmol/mg of protein, which corresponded to 48-fold purification from the ndcrosomes was observed. The purified protein produced a single major band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis having a molecular weight of 55,000. Using Western blotting, the band immunochemiadly cross-reacted with antibody which had been raised against rat liver cytochrome p-450mc-i.The purified preparation efficiently catalyzed benzo(a)pyrene hydroxylation and 7-ethoxycoumarin 0-deethylation when reconstituted with NADPH-cyto-chrome P-450 reductase. These activities were inhibited by 7,8-benzoflavone as well as anti-cytochrome p-450mc-iantibody, but not by p-450pb-iantibody. The results indicate that, in mouse skin microsomes, a cytochrome P-450 induced by benz(a)anthracene is enzymatically and immunochemically similar to rat liver cytochrome p-450mc-i-It is suggested that this enzyme plays an important role in the activation of carcinogenic polycyclic aromatic hydrocarbons.
|Number of pages||4|
|Publication status||Published - 1989 Feb 15|
ASJC Scopus subject areas
- Cancer Research