Premium
Molecular diversity of sterol 14α‐demethylase substrates in plants, fungi and humans
Author(s) -
Lamb David C,
Kelly Diane E,
Kelly Steven L
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00247-6
Subject(s) - lanosterol , demethylation , chemistry , sterol , biochemistry , substrate (aquarium) , candida albicans , biology , cholesterol , microbiology and biotechnology , gene , gene expression , ecology , dna methylation
Metabolism of lanosterol (LAN), 24‐methylene‐24,25‐dihydrolanosterol (24‐methyleneDHL), dihydrolanosterol (DHL) and obtusifoliol (OBT) by purified human, plant ( Sorghum bicolor ) and fungal ( Candida albicans ) sterol 14α‐demethylase (CYP51; P450 14DM ) reconstituted with NADPH cytochrome P450 reductases was studied in order to elucidate the substrate specificity and sterol stereo‐ and regio‐structural requirements for optimal CYP51 activity. Both human and C. albicans CYP51 could catalyse 14α‐demethylation of each substrate with varying levels of activity, but having slightly higher activity for their respective endogenous substrates in vivo, dihydrolanosterol for human CYP51 ( V max =0.5 nmol/min/nmol CYP51) and 24‐methylene‐24,25‐dihydrolanosterol for C. albicans CYP51 ( V max =0.3 nmol/min/nmol CYP51). In contrast, S. bicolor CYP51 showed strict substrate specificity and selectivity towards its own endogenous substrate, obtusifoliol ( V max =5.5 nmol/min/nmol CYP51) and was inactive towards 14α‐demethylation of lanosterol, 24‐methylene‐24,25‐dihydrolanosterol and dihydrolanosterol. These findings confirm that the presence of the 4β‐methyl group in the sterol molecule renders the plant CYP51 incapable of 14α‐demethylation thus revealing the strict active site conservation of plant CYP51 during evolution.