OCCURRENCE OF A P450 SHOWING HIGH HOMOLOGY TO YEAST LANOSTEROL 14-DEMETHYLASE (P450(14DM)) IN THE RAT-LIVER

The rat liver cDNA Library in lambda gt11 was screened with the antisera against rat liver lanosterol 14 alpha-demethylase (P450(14DM)), and one clone (pRT-9) was isolated. The open reading frame of pRT-9 cDNA showed high homology to yeast P450(14DM) (48.9 % in nucleotides and 37.7 % in amino acids). Homology of the heme-binding region of pRT-9 protein to that of yeast P450(14DM) was 80 %. Three additional regions showing more than 60 % homology were identified and one of them was assignable as the distal helix. These findings suggest that pRT-9 protein is P450(14DM) and P450(14DMs) of rat and yeast may be orthologous. This is the first evidence suggesting the occurrence of orthologous P450 in widely diverged species. (C) 1994 Academic Press, Inc.