Steroid 11 β -hydroxylase
| Steroid 11 β -hydroxylase | ||
|---|---|---|
| Mass / length primary structure | 503 amino acids | |
| Secondary to quaternary structure | mitochondrial membrane protein | |
| Cofactor | Hamm | |
| Identifier | ||
| Gene name (s) | CYP11B1 , CYP11B2 | |
| External IDs | ||
| Enzyme classification | ||
| EC, category | 1.14.15.4 , monooxygenase | |
| Response type | Hydroxylation | |
| Substrate | Steroid + red. adr. Ferredoxin + O 2 | |
| Products | 11beta-hydroxysteroid + oxide. adr. Ferredoxin + H 2 O | |
| Occurrence | ||
| Homology family | Cytochrome A / B family | |
| Parent taxon | Jaws | |
Steroid 11 β -hydroxylase (also: 11 β monooxygenase) hot enzymes which catalyze the hydroxylation of steroids at the 11-position catalyze . They are indispensable in the steroid hormone metabolism of vertebrates and in biotransformation . There are two 11 β -hydroxylases in humans : CYP11B1 and CYP11B2 . The main activity is in the adrenal gland (adrenal steroid synthesis).
As part of an enzyme cascade, mineralocorticoids , glucocorticoids and sex hormones are produced in the adrenal cortex . Enzyme defects in this cascade lead to a lack of cortisol . Depending on the enzyme concerned, different alternative metabolic pathways are used, which lead to an increased accumulation of different steroid hormones. The relatively rare lack of 11 β -hydroxylase leads to a rare variant of the congenital adrenal hyperplasia (AGS IV), the CAH by 11-beta-hydroxylase deficiency . This differs from more common forms of the adrenogenital syndrome in that the blood pressure is too high (hypertension) and is therefore also called adrenogenital hypertension syndrome. The reason for this is the impaired conversion of 11-deoxycortisol (DOC) to aldosterone and the associated increase in DOC. This has the effect of increasing blood pressure.
Medicines such as metopirone are used as inhibitors of steroid 11 β -hydroxylase.
Catalyzed reaction
+ Ferredoxin red. + O 2 ⇒
⇒ 
+ ferredoxin ox. + H 2 O
Progesterone is converted to 11β-hydroxyprogesterone. Other natural substrates are 11-deoxycortisone , 11-deoxycortisol , cortisone , 18-hydroxycortisone and, in the fungus Absidia coerulea , 16.17 α- epoxyprogesterone .
