. "Catalysis of the reaction: 5beta-cholestane-3alpha,7alpha-diol + H(+) + NADPH + O(2) = 5beta-cholestane-3alpha,7alpha,12alpha-triol + H(2)O + NADP(+)." . . "CYP8B1" . "cytochrome P450 8B1" . "sterol 12alpha-hydroxylase activity" . "5beta-cholestane-3alpha,7alpha-diol 12alpha-hydroxylase activity" . "5beta-cholestane-3alpha,7alpha-diol 12alpha-monooxygenase activity" . "5beta-cholestane-3alpha,7alpha-diol,NADPH:oxygen oxidoreductase (12alpha-hydroxylating) activity" . . .