| abstract |
cytochrome P450 family 11, subfamily B subfamily. Cytochrome P450 11B (CYP11B) enzymes catalyze the final steps in the production of glucocorticoids and mineralocorticoids that takes place in the adrenal gland. There are two human CYP11B isoforms: Cyb11B1 (11-beta-hydroxylase or P45011beta), which catalyzes the final step of cortisol synthesis by a one-step reaction from 11-deoxycortisol; and CYP11B2 (aldosterone synthase or P450aldo), which catalyzes three steps in the synthesis of aldosterone. The CYP11B subfamily belongs to the large cytochrome P450 (P450, CYP) superfamily of heme-containing proteins that catalyze a variety of oxidative reactions of a large number of structurally different endogenous and exogenous compounds in organisms from all major domains of life. CYPs bind their diverse ligands in a buried, hydrophobic active site, which is accessed through a substrate access channel formed by two flexible helices and their connecting loop. |