Open AccessInteraction of CYP11B1 (cytochrome P‐450 11β ) with CYP11A1 (cytochrome P‐450 scc ) in COS‐1 cells
Author(s) -
Cao Peirang,
Bernhardt Rita
Publication year - 1999
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.1999.00414.x
Subject(s) - adrenodoxin , steroid 11 beta hydroxylase , cholesterol side chain cleavage enzyme , cytochrome , aldosterone synthase , corticosterone , cytochrome p450 , aldosterone , chemistry , steroid , biology , endocrinology , medicine , microbiology and biotechnology , biochemistry , enzyme , metabolism , renin–angiotensin system , blood pressure , hormone
The interactions of CYP11B1 (cytochrome P‐450 11β ), CYP11B2 (cytochrome P‐450 aldo ) and CYP11A1 (cytochrome P‐450 scc ) were investigated by cotransfection of their cDNA into COS‐1 cells. The effect of CYP11A1 on CYP11B isozymes was examined by studying the conversion of 11‐deoxycorticosterone to corticosterone, 18‐hydroxycorticosterone and aldosterone. It was shown that when human or bovine CYP11B1 and CYP11A1 were cotransfected they competed for the reducing equivalents from the limiting source contained in COS‐1 cells; this resulted in a decrease of the CYP11B activities without changes in the product formation patterns. The competition of human CYP11A1 with human CYP11B1 and CYP11B2 could be diminished with excess expression of bovine adrenodoxin. However, the coexpression of bovine CYP11B1 and CYP11A1 in the presence of adrenodoxin resulted in a stimulation of 11β‐hydroxylation activity of CYP11B1 and in a decrease of the 18‐hydroxycorticosterone and aldosterone formation. These results suggest that the interactions of CYP11A1 with CYP11B1 and CYP11B2 do not have an identical regulatory function in human and in bovine adrenal tissue.