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Steroidogenic enzymes are

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s that are involved in

steroidogenesis A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

and

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

biosynthesis Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecul ...

. They are responsible for the

of the

steroid hormone A steroid hormone is a steroid that acts as a hormone. Steroid hormones can be grouped into two classes: corticosteroids (typically made in the adrenal cortex, hence ''cortico-'') and sex steroids (typically made in the gonads or placenta). Withi ...

s, including

sex steroid Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effect ...

s (

androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

s, and

progestogen Progestogens, also sometimes written progestagens or gestagens, are a class of natural or synthetic steroid hormones that bind to and activate the progesterone receptors (PR). Progesterone is the major and most important progestogen in the bod ...

s) and

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

s ( glucocorticoids and

mineralocorticoid Mineralocorticoids are a class of corticosteroids, which in turn are a class of steroid hormones. Mineralocorticoids are produced in the adrenal cortex and influence salt and water balances ( electrolyte balance and fluid balance). The primary ...

s), as well as

neurosteroid Neurosteroids, also known as neuroactive steroids, are endogenous or exogenous steroids that rapidly alter neuronal excitability through interaction with ligand-gated ion channels and other cell surface receptors. The term ''neurosteroid'' was co ...

s, from

cholesterol Cholesterol is any of a class of certain organic molecules called lipids. It is a sterol (or modified steroid), a type of lipid. Cholesterol is biosynthesized by all animal cells and is an essential structural component of animal cell memb ...

. Steroidogenic enzymes are most highly expressed in classical steroidogenic tissues, such as the

testis A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...

ovary The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. ...

, and

adrenal cortex The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is ...

, but are also present in other tissues in the body.

List of steroidogenic enzymes

* Steroid desmolases **

Cholesterol side-chain cleavage enzyme Cholesterol side-chain cleavage enzyme is commonly referred to as P450scc, where "scc" is an acronym for side-chain cleavage. P450scc is a mitochondrial enzyme that catalyzes conversion of cholesterol to pregnenolone. This is the first reactio ...

(20,22-desmolase) – steroid synthesis ** 17,20-Lyase (17,20-desmolase) – androgen synthesis *

Steroid hydroxylase A steroid hydroxylase is a class of hydroxylase enzymes involved in the biosynthesis of steroids. See also * Steroidogenic enzyme Additional images File:Steroidogenesis.svg, Steroidogenesis A steroid is a biologically active organic comp ...

s ** 11β-Hydroxylase – corticosteroid synthesis **

17α-Hydroxylase Cytochrome P450 17A1 (steroid 17α-monooxygenase, 17α-hydroxylase, 17-alpha-hydroxylase, 17,20-lyase, 17,20-desmolase) is an enzyme of the hydroxylase type that in humans is encoded by the ''CYP17A1'' gene on chromosome 10. It is ubiquitously exp ...

– androgen and glucocorticoid synthesis **

18-Hydroxylase 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 ...

(aldosterone synthase) – mineralocorticoid synthesis **

21-Hydroxylase Steroid 21-hydroxylase (also known as steroid 21-monooxygenase, cytochrome P450C21, 21α-hydroxylase and less commonly 21β-hydroxylase) is an enzyme that hydroxylates steroids at the C21 position and is involved in biosynthesis of aldosterone a ...

– corticosteroid synthesis **

Cytochrome P450 Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various co ...

(

CYP1 Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various comp ...

, 2, 3) – estrogen metabolism *

Hydroxysteroid dehydrogenase Hydroxysteroid dehydrogenases (HSDs) are a group of alcohol oxidoreductases that catalyze the dehydrogenation of hydroxysteroids. These enzymes also catalyze the reverse reaction, acting as ketosteroid reductases (KSRs). There are four types, cl ...

s (and ketosteroid reductases) ** 3α-Hydroxysteroid dehydrogenase – androgen, progestogen, and neurosteroid synthesis and metabolism ** 3β-Hydroxysteroid dehydrogenase/Δ^5-4-isomerase ( 1, 2) – androgen, progestogen, and neurosteroid synthesis ** 11β-Hydroxysteroid dehydrogenase ( 1, 2) – corticosteroid synthesis and metabolism **

17β-Hydroxysteroid dehydrogenase A hydroxysteroid is a molecule derived from a steroid with a hydrogen replaced with a hydroxy group. When the hydroxy group is specifically at the C3 position, hydroxysteroids are referred to as sterols, with an example being cholesterol. See ...

( 1– 15) – androgen, estrogen, and progestogen synthesis and metabolism ** 20α-Hydroxysteroid dehydrogenase – progestogen synthesis and metabolism **

20β-Hydroxysteroid dehydrogenase In enzymology, a 3alpha(or 20beta)-hydroxysteroid dehydrogenase () is an enzyme that catalyzes the chemical reaction : androstan-3alpha,17beta-diol + NAD+ \rightleftharpoons 17beta-hydroxyandrostan-3-one + NADH + H+ Thus, the two substrates of ...

– progestogen synthesis and metabolism Trimethyl steroid-nomenclature

* Steroid reductases **

5α-Reductase 5α-Reductases, also known as 3-oxo-5α-steroid 4-dehydrogenases, are enzymes involved in steroid metabolism. They participate in three metabolic pathways: bile acid biosynthesis, androgen and estrogen metabolism. There are three isozymes o ...

( 1, 2, 3) – androgen and neurosteroid synthesis, progestogen metabolism ** 5β-Reductase – androgen and progestogen metabolism, neurosteroid synthesis *

Conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change ...

(and deconjugation) **

Glucuronosyltransferase Uridine 5'-diphospho-glucuronosyltransferase ( UDP-glucuronosyltransferase, UGT) is a microsomal glycosyltransferase () that catalyzes the transfer of the glucuronic acid component of UDP-glucuronic acid to a small hydrophobic molecule. This is ...

( UGT2Bs) – steroid metabolism **

Glucuronidase Glucuronidase may refer to several enzymes: * Alpha-glucuronidase * Beta-glucuronidase * Glycyrrhizinate beta-glucuronidase * Glucuronosyl-disulfoglucosamine glucuronidase In enzymology, a glucuronosyl-disulfoglucosamine glucuronidase () is an e ...

( β-glucuronidase) – steroid synthesis ** Steroid sulfotransferase ( SULT1A1, 1E1, 2A1, 2B1a, 2B1b) – steroid metabolism, neurosteroid synthesis **

Steroid sulfatase Steroid sulfatase (STS), or steryl-sulfatase (EC 3.1.6.2), formerly known as arylsulfatase C, is a sulfatase enzyme involved in the metabolism of steroids. It is encoded by the ''STS'' gene. Reactions This enzyme catalyses the following chemi ...

– steroid synthesis, neurosteroid metabolism * Others **

Aromatase Aromatase (), also called estrogen synthetase or estrogen synthase, is an enzyme responsible for a key step in the biosynthesis of estrogens. It is CYP19A1, a member of the cytochrome P450 superfamily, which are monooxygenases that catalyze many ...

(estrogen synthetase) – estrogen synthesis

References

{{Cholesterol and steroid metabolism enzymes Enzymes Steroids