Steroid 21 hydroxylase

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Steroid 21 hydroxylase
Steroid 21 hydroxylase
3D structure with heme (red) according to PDB  2GEG (theor.)
Properties of human protein
Mass / length primary structure 494 amino acids; 55.9 kDa
Cofactor Heme thiolate
Identifier
Gene names CYP21A2  ; CPS1; CA21H; CAH1; CYP21; CYP21B; MGC150536; MGC150537; P450c21B
External IDs
Enzyme classification
EC, category 1.14.99.10 ,  oxidoreductase
Response type Hydroxylation
Substrate Steroid + AH 2 + O 2
Products 21-hydroxysteroid + A + H 2 O
Occurrence
Parent taxon Jaws
Orthologue
human mouse
Entrez 1589 13079
Ensemble ENSG00000168482 ENSMUSG00000024365
UniProt P08686 A0JP50
Refseq (mRNA) NM_000500 NM_009995
Refseq (protein) NP_000491 NP_034125
Gene locus Chr c6_COX: 32.1 - 32.1 Mb Chr 17: 34.41 - 34.41 Mb
PubMed search 1589 13079

Steroid-21- hydroxylase ( CYP21 ) is an enzyme that is involved in the biosynthesis of the steroid hormones aldosterone and cortisol . It catalyzes an oxidation of the carbon atom in steroids , which is necessary for the formation of these hormones.

21-hydroxylase is produced by the gene CYP21A2 . A defect within this gene causes a disruption in the formation of the enzyme, which leads to adrenogenital syndrome type 3 ( classic 21-OHD CAH ).

The reason for the frequent mutations of the gene lies in the recombination with an inactive pseudogene with which it lies on a chromosome.

Catalyzed reactions

Pregnenolone+ A H 2 + O 2 ⇒ 21-OH pregnenolone+ A + H 2 O

Pregnenolone is converted to 21-hydroxypregnenolone.

17α-OH-pregnenolone+ A H 2 + O 2 ⇒ 17α, 21-dihydroxypregnenolone+ A + H 2 O

17 α -hydroxypregnenolone becomes 17 α , 21-oxidized Dihydroxypregnenolon.

17α-hydroxyprogesterone+ A H 2 + O 2 ⇒ 11-deoxycortisol+ A + H 2 O

17 α -Hydroxyprogesterone is converted to 11-Deoxycortisol.

11β-hydroxyprogesterone+ A H 2 + O 2 ⇒ Corticosterone+ A + H 2 O

11 β- Hydroxyprogesterone is hydroxylated, corticosterone is formed.

Web links

Wikibooks: Biochemistry and Pathobiochemistry: Steroid Hormone Metabolism  - Learning and Teaching Materials

Individual evidence

  1. ^ G. Löffler, PE Petrides, PC Heinrich: Biochemie & Pathobiochemie. 9th edition, Springer, Heidelberg 2014, ISBN 978-3-642-17971-6 , p. 501.