Search results
Results from the WOW.Com Content Network
Aldosterone synthase, also called steroid 18-hydroxylase, corticosterone 18-monooxygenase or P450C18, is a steroid hydroxylase cytochrome P450 enzyme involved in the biosynthesis of the mineralocorticoid aldosterone and other steroids. The enzyme catalyzes sequential hydroxylations of the steroid angular methyl group at C18 after initial 11β ...
Cholesterol side-chain cleavage enzyme (20,22-desmolase) – steroid synthesis; 17,20-Lyase (17,20-desmolase) – androgen synthesis; Steroid hydroxylases. 11β-Hydroxylase – corticosteroid synthesis; 17α-Hydroxylase – androgen and glucocorticoid synthesis; 18-Hydroxylase (aldosterone synthase) – mineralocorticoid synthesis
These enzymes are nearly identical (they share 11β-hydroxylation and 18-hydroxylation functions), but aldosterone synthase is also able to perform an 18-oxidation. Moreover, aldosterone synthase is found within the zona glomerulosa at the outer edge of the adrenal cortex; 11β-hydroxylase is found in the zona glomerulosa and zona fasciculata.
The enzyme has steroid 18-hydroxylase activity to synthesize aldosterone and other steroids. Aldosterone synthase is found within the zona glomerulosa at the outer edge of the adrenal cortex. Aldosterone synthase normally is not ACTH sensitive, and is only activated by angiotensin II. [citation needed]
The outermost layer, the zona glomerulosa is the main site for the production of aldosterone, a mineralocorticoid. The synthesis and secretion of aldosterone are mainly regulated by the renin–angiotensin–aldosterone system. The zona glomerulosa cells express a specific enzyme aldosterone synthase (also known as CYP11B2).
A simplified reaction mechanism for N-acetylglutamate synthase (NAGS). Two mechanisms for N-acetyltransferase function have been proposed: a two-step, ping-pong mechanism involving transfer of the relevant acetyl group to an activated cysteine residue [10] and a one-step mechanism through direct attack of the amino nitrogen on the carbonyl group. [11]
HMG-CoA synthase: Acetoacetyl-CoA condenses with another Acetyl-CoA molecule to form 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). HMG-CoA reductase: HMG-CoA is reduced to mevalonate by NADPH. This is the rate limiting step in cholesterol synthesis, which is why this enzyme is a good target for pharmaceuticals . mevalonate-5-kinase
(The other differences between the diagrams are not of consequence.) Cortisone. Cortisol, a glucocorticoid, binds the glucocorticoid receptor. However, because of its molecular similarity to aldosterone it also binds the mineralcorticoid receptor at higher concentrations. Both aldosterone and cortisol have a similar affinity for the ...