Reconstruction of aryl hydrocarbon hydroxylase from rabbit intestinal mucosa microsomes

Benzo(a)pyene hydroxylation activity was solubilized from rabbit intestinal mucosa microsomes and reconstituted with a cytochrome P-450 preparation obtained by fractionation with 6-amino-n-hexyl Sepharose 4B, hydroxylapatite and CM-Sephadex C-50, and partially purified NADPH-cytochrome c reductase. Phosphatidylserine was required for the maximal activity, while phosphatidylcholine had no stimulatory effect. The carbon monoxide difference spectrum of the cytochrome P-450 fraction showed a maximum peak at 450 nm. Although another cytochrome P-450 fraction was active for hexadecane hydroxylation, this fraction had little activity. The results indicate that more than one cytochrome P-450 exists in the intestinal mucosa microsomes.