X-Nico

unusual facts about 21-Hydroxylase


Cytochrome P450 reductase

Five missense mutations (A284P, R454H, V489E, C566Y, and V605F) and a splicing mutation in the POR genes have been found in patients who had hormonal evidence for combined deficiencies of two steroidogenic cytochrome P450 enzymes - P450c17 CYP17A1, which catalyzes steroid 17α-hydroxylation and 17,20 lyase reaction, and P450c21 21-Hydroxylase, which catalyzes steroid 21-hydroxylation.


7α-Hydroxy-4-cholesten-3-one

It is metabolized by the enzyme 7α-hydroxycholest-4-en-3-one 12α-hydroxylase to 7α,12α-dihydroxycholest-4-en-3-one and then to cholic acid, the major primary bile acid in humans.

8-Prenylnaringenin

The enzyme 8-dimethylallylnaringenin 2'-hydroxylase uses sophoraflavanone B (8-prenylnaringenin), NADPH, H+ and O2 to produce leachianone G, NADP+ and H2O.

Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency

Mineralocorticoid manifestations of severe 11β-hydroxylase deficient CAH can be biphasic, changing from deficiency (salt-wasting) in early infancy to excess (hypertension) in childhood and adult life.

Because 11β-hydroxylase activity is not necessary in the production of sex steroids (androgens and estrogens), the hyperplastic adrenal cortex produces excessive amounts of DHEA, androstenedione, and especially testosterone.

Etomidate

Etomidate suppresses corticosteroid synthesis in the adrenal cortex by reversibly inhibiting 11-beta-hydroxylase, an enzyme important in adrenal steroid production; it leads to primary adrenal suppression.


see also