Steroidogenic acute regulatory protein, mitochondrial
向ステロイド性急性調節タンパク質（ハーパー563ページ）
http://www.uniprot.org/uniprot/P49675
ステロイドホルモンの合成において、コレステロールをプレグネノロンに変換する際にコレステロールをミトコンドリア内膜に運ぶことで促進的に働く。
Plays a key role in steroid hormone synthesis by enhancing the metabolism of cholesterol into pregnenolone. Mediates the transfer of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane where it is cleaved to pregnenolone.
性腺、副腎、腎臓で発現している。ミトコンドリアの膜間腔に局在する。
Cholesterol side-chain cleavage enzyme, mitochondrial
http://www.uniprot.org/uniprot/P05108
Catalyzes the side-chain cleavage reaction of cholesterol to pregnenolone.
Catalytic activity
Cholesterol + 6 reduced adrenodoxin + 3 O2 = pregnenolone + 4-methylpentanal + 6 oxidized adrenodoxin + 4 H2O.
Cofactor
Heme group.
Cholesterol side-chain cleavage enzyme, mitochondrial (EC:1.14.15.6)
Alternative name(s):
CYPXIA1
Cholesterol desmolase
Cytochrome P450 11A1
Cytochrome P450(scc)
3 beta-hydroxysteroid dehydrogenase/Delta 5-->4-isomerase type 1 (HSD3B1)
http://www.uniprot.org/uniprot/P14060
二機能酵素。ステロイド合成で重要な役割をもつ。プレグネノロンをプロゲステロンに、17-ヒドロキシプレグネノロンを17-ヒドロキシプロゲステロンへ、DHEAを4-アンドロステジオンにジヒドロテストステロンを5-アンドロスタン3,17ジオールに変換する。
3-beta-HSD is a bifunctional enzyme, that catalyzes the oxidative conversion of Delta(5)-ene-3-beta-hydroxy steroid, and the oxidative conversion of ketosteroids. The 3-beta-HSD enzymatic system plays a crucial role in the biosynthesis of all classes of hormonal steroids. Efficiently catalyzes the transformation of pregnenolone to progesterone, 17-alpha-hydroxypregnenolone to 17-alpha-hydroxyprogesterone, DHEA to 4-androstenedione, dihydrotestosterone to 5-alpha-androstane-3 beta,17 beta-diol, dehydroepiandrosterone to androstenedione and 5-alpha-androstan-3 beta,17 beta-diol to 5-alpha-dihydrotestosterone.
Catalytic activityi
A 3-beta-hydroxy-Delta(5)-steroid + NAD+ = a 3-oxo-Delta(5)-steroid + NADH.
A 3-oxo-Delta(5)-steroid = a 3-oxo-Delta(4)-steroid.
Steroid 21-hydroxylase (CYP21A2)
http://www.uniprot.org/uniprot/P08686
Specifically catalyzes the 21-hydroxylation of steroids. Required for the adrenal synthesis of mineralocorticoids and glucocorticoids.
Catalytic activityi
A C(21) steroid + (reduced NADPH--hemoprotein reductase) + O2 = a 21-hydroxy-C(21)-steroid + (oxidized NADPH--hemoprotein reductase) + H2O.
Cofactori
Heme group.
Cytochrome P450 11B1, mitochondrial (CYP11B1)
http://www.uniprot.org/uniprot/P15538
Function
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.
Catalytic activity
A steroid + reduced adrenodoxin + O2 = an 11-beta-hydroxysteroid + oxidized adrenodoxin + H2O.
Cofactor
Heme group.
Cytochrome P450 11B2, mitochondrial (CYP11B2)
Preferentially catalyzes the conversion of 11-deoxycorticosterone to aldosterone via corticosterone and 18-hydroxycorticosterone.1 Publication
Catalytic activity
A steroid + reduced adrenodoxin + O2 = an 11-beta-hydroxysteroid + oxidized adrenodoxin + H2O.1 Publication
Corticosterone + reduced adrenodoxin + O2 = 18-hydroxycorticosterone + oxidized adrenodoxin + H2O.1 Publication
Cofactor
Heme group.
Recommended name:
Cytochrome P450 11B2, mitochondrial
Alternative name(s):
Aldosterone synthase (EC:1.14.15.4, EC:1.14.15.5)
Short name:
ALDOS
Aldosterone-synthesizing enzyme
CYPXIB2
Cytochrome P-450Aldo
Cytochrome P-450C18
Steroid 18-hydroxylase
Involvement in disease
Corticosterone methyloxidase 1 deficiency (CMO-1 deficiency) [MIM:203400]: Autosomal recessive disorder of aldosterone biosynthesis. There are two biochemically different forms of selective aldosterone deficiency be termed corticosterone methyloxidase (CMO) deficiency type 1 and type 2. In CMO-1 deficiency, aldosterone is undetectable in plasma, while its immediate precursor, 18-hydroxycorticosterone, is low or normal.
Steroid 17-alpha-hydroxylase/17,20 lyase
http://www.uniprot.org/uniprot/P05093
Steroid 17-alpha-hydroxylase/17,20 lyase (EC:1.14.99.9, EC:4.1.2.30)
Alternative name(s):
17-alpha-hydroxyprogesterone aldolase
CYPXVII
Cytochrome P450 17A1
Cytochrome P450-C17
Short name:
Cytochrome P450c17
Steroid 17-alpha-monooxygenase
Function
プレグネノロンとプロゲステロンを17-α水酸化物に変換する。そしてそれに続くデヒドロエピアンドロステロンおよびアンドロステジオンに変換する。
17位α水酸化と17位と20位のリアーゼ反応を触媒する。胎生期、思春期の性徴に関連する。
Conversion of pregnenolone and progesterone to their 17-alpha-hydroxylated products and subsequently to dehydroepiandrosterone (DHEA) and androstenedione. Catalyzes both the 17-alpha-hydroxylation and the 17,20-lyase reaction. Involved in sexual development during fetal life and at puberty.1 Publication
Catalytic activity
A C(21)-steroid + (reduced NADPH--hemoprotein reductase) + O2 = a 17-alpha-hydroxy-C(21)-steroid + (oxidized NADPH--hemoprotein reductase) + H2O.1 Publication
17-alpha-hydroxyprogesterone = androst-4-ene-3,17-dione + acetaldehyde.1 Publication
Cofactoi
Heme group.1 Publication
Enzyme regulation
Regulated predominantly by intracellular cAMP levels.
Pathway
Lipid metabolism; steroid biosynthesis.
Post-translational modification
Phosphorylation is necessary for 17,20-lyase, but not for 17-alpha-hydroxylase activity.1 Publication
17,20-リアーゼ活性にはリン酸化修飾が必須である。
Pathology & Biotechi
Involvement in disease
Adrenal hyperplasia 5 (AH5) [MIM:202110]: 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).15 Publications
Note: The disease is caused by mutations affecting the gene represented in this entry.
Testosterone 17-beta-dehydrogenase 3 (HSD17B3)
Favors the reduction of androstenedione to testosterone. Uses NADPH while the two other EDH17B enzymes use NADH.
Catalytic activity
Testosterone + NADP+ = androst-4-ene-3,17-dione + NADPH.
Aromatase (CYP19A1)
http://www.uniprot.org/uniprot/P11511
Catalyzes the formation of aromatic C18 estrogens from C19 androgens.
Catalytic activityi
Testosterone + 3 O2 + 3 reduced flavoproteins = 17-beta-estradiol + formate + 4 H2O + 3 oxidized flavoproteins.
Androst-4-ene-3,17-dione + 3 O2 + 3 reduced flavoproteins = estrone + formate + 4 H2O + 3 oxidized flavoproteins.
Cofactori
Heme group.
Recommended name:
Aromatase (EC:1.14.14.14)
Alternative name(s):
CYPXIX
Cytochrome P-450AROM
Cytochrome P450 19A1
Estrogen synthase
