Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
A microsomal cytochrome P-450 (heme-thiolate) protein that catalyses two independent reactions at the same active site - the 17-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis (EC 184.108.40.206), and the conversion of the 17-hydroxylated products via a 17,20-lyase reaction to form androstenedione and 3beta-hydroxyandrost-5-en-17-one, leading to sex hormone biosynthesis. The activity of this reaction is dependent on the allosteric interaction of the enzyme with cytochrome b5 without any transfer of electrons from the cytochrome [2,4]. The enzymes from different organisms differ in their substrate specificity. While the enzymes from pig, hamster, and rat accept both 17alpha-hydroxyprogesterone and 17alpha-hydroxypregnenolone, the enzymes from human, bovine, sheep, goat, and bison do not accept the former, and the enzyme from guinea pig does not accept the latter .
17,20 lyase, 17-20 lyase, 17-alpha-hydroxylase/C17-20 lyase, 17-hydroxylase/C17,20-lyase, 17alpha-hydroxylase, 17alpha-hydroxylase-C(17,20)-lyase, 17alpha-hydroxylase-C17,20-lyase, 17alpha-hydroxylase/17,20 lyase, 17alpha-hydroxylase/17,20-lyase, 17alpha-hydroxylase/17,20-lyase cytochrome P450, more