CYP11B1 cDNA Clone – Cytochrome P450, Family 11, Subfamily B, Polypeptide 1 (Human)

This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the mitochondrial inner membrane and is involved in the conversion of progesterone to cortisol in the adrenal cortex. Mutations in this gene cause congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency. Transcript variants encoding different isoforms have been noted for this gene. [provided by RefSeq, Jul 2008]

CYP11B1: Has steroid 11-beta-hydroxylase activity. In addition to this activity, the 18 or 19-hydroxylation of steroids and the aromatization of androstendione to estrone have also been ascribed to cytochrome P450 XIB. Defects in CYP11B1 are the cause of adrenal hyperplasia type 4 (AH4). AH4 is a form of congenital adrenal hyperplasia, a common recessive disease due to defective synthesis of cortisol. Congenital adrenal hyperplasia is characterized by androgen excess leading to ambiguous genitalia in affected females, rapid somatic growth during childhood in both sexes with premature closure of the epiphyses and short adult stature. Four clinical types: salt wasting (SW, the most severe type), simple virilizing (SV, less severely affected patients), with normal aldosterone biosynthesis, non-classic form or late onset (NC or LOAH), and cryptic (asymptomatic). AH4 patients usually have hypertension. Defects in CYP11B1 are a cause of familial hyperaldosteronism type 1 (FH1). It is a disorder characterized by hypertension, variable hyperaldosteronism, and abnormal adrenal steroid production, including 18-oxocortisol and 18-hydroxycortisol. There is significant phenotypic heterogeneity, and some individuals never develop hypertension. The molecular defect causing hyperaldosteronism familial type 1 is an anti-Lepore-type fusion of the CYP11B1 and CYP11B2 genes. The hybrid gene has the promoting part of CYP11B1, ACTH-sensitive, and the coding part of CYP11B2. Belongs to the cytochrome P450 family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Oxidoreductase; Mitochondrial; Lipid Metabolism - C21-steroid hormone; Lipid Metabolism - androgen and estrogen; EC 1.14.15.4

Chromosomal Location of Human Ortholog: 8q21

Cellular Component: mitochondrial inner membrane; mitochondrion

Molecular Function: corticosterone 18-monooxygenase activity; heme binding; oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen, NADH or NADPH as one donor, and incorporation of one atom of oxygen; steroid 11-beta-monooxygenase activity

Biological Process: aldosterone biosynthetic process; C21-steroid hormone biosynthetic process; cellular response to hormone stimulus; cholesterol metabolic process; glucocorticoid biosynthetic process; glucose homeostasis; immune response; regulation of blood pressure; sterol metabolic process

Disease: Adrenal Hyperplasia, Congenital, Due To Steroid 11-beta-hydroxylase Deficiency; Glucocorticoid-remediable Aldosteronism