21-Hydroxylase

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Cytochrome P450, family 21, subfamily A, polypeptide 2
Identifiers
Symbol(s)	CYP21A2; CPS1; CA21H; CAH1; CYP21; CYP21B; MGC150536; MGC150537; P450c21B
External IDs	OMIM: 201910 MGI: 88591 Homologene: 68063
Gene ontology Molecular Function: • monooxygenase activity • steroid 21-monooxygenase activity • steroid binding • iron ion binding • lipid binding • oxygen binding • heme binding • metal ion binding Cellular Component: • endoplasmic reticulum • microsome • membrane Biological Process: • electron transport • C21-steroid hormone biosynthetic process
RNA expression pattern
Image:PBB GE CYP21A2 214622 at tn.png More reference expression data
Orthologs
	Human	Mouse
Entrez	1589	13079
Ensembl	ENSG00000168482	ENSMUSG00000024365
Uniprot	P08686	A0JP50
Refseq	NM_000500 (mRNA) NP_000491 (protein)	NM_009995 (mRNA) NP_034125 (protein)
Location	Chr c6_COX: 32.1 - 32.1 Mb	Chr 17: 34.41 - 34.41 Mb
Pubmed search	[1]	[2]

Steroid 21-hydroxylase (or steroid 21-monooxygenase or 21α-Hydroxylase; EC 1.14.99.10) is a cytochrome P450 enzyme which is involved with the biosynthesis of the steroid hormones aldosterone and cortisol.

The CAS number is 9029-68-9.

21-Hydroxylase is encoded by the gene CYP21B.

Contents 1 Reaction 2 Pathway 3 Clinical significance 4 References 5 Further reading 6 External links

Reaction

It catalyses the hydroxylation of the carbon atom 21 in steroids (adding an "–OH"), which is necessary with the formation of these hormones.

Progesterone

Deoxycorticosterone.svg 11-deoxycorticosterone

Steroid-nomenclature.png Steroid numbering - #21 is near center top

Pathway

Clinical significance

A defect within the CYP21B gene causes a disturbance of the development of the enzyme, which leads to congenital adrenal hyperplasia due to 21-hydroxylase deficiency. A related pseudogene is located near this gene; gene conversion events involving the functional gene and the pseudogene are thought account for many cases of steroid 21-hydroxylase deficiency.^[1]

References

Further reading

External links

• Synthesis of Desoxycorticosterone from Progesterone through 21-Hydroxylase (Image)
• MeSH Steroid+21-Hydroxylase

de:21-Hydroxylase

v • d • e Oxidoreductases: dioxygenases, including steroid hydroxylases (EC 1.14)
1.14.11 - 2-oxoglutarate	Prolyl hydroxylase - Lysyl hydroxylase
1.14.13 - NADH or NADPH	Flavin-containing monooxygenase - Nitric oxide synthase - Cholesterol 7 alpha-hydroxylase - Methane monooxygenase - 3A4 -51A1
1.14.14 - reduced flavin or flavoprotein	19A1 - 2D6 - 2E1
1.14.15 - reduced iron-sulfur protein	11B1 - 11B2 - 11A1
1.14.16 - reduced pteridine	Phenylalanine hydroxylase - Tyrosine hydroxylase - Tryptophan hydroxylase
1.14.17 - reduced ascorbate	Dopamine beta hydroxylase
1.14.18-19 - other	Tyrosinase - Stearoyl-CoA desaturase-1
1.14.99 - miscellaneous	Cyclooxygenase - Heme oxygenase (HMOX1) - Squalene monooxygenase - 17A1 - 21A2

Template:Steroid hydroxylases

v • d • e Cytochromes, oxygenases: cytochrome P450 (EC 1.14)
CYP1	A1, A2, B1
CYP2	A6, A7, A13, B6, C8, C9, C18, C19, D6, E1, F1, J2, R1, S1, U1, W1
CYP3	A4, A5, A7, A43
CYP4	A11, A22, B1, F2, F3, F8, F11, F12, F22, V2, X1, Z1
CYP5-20	CYP5 (A1) - CYP7 (A1, B1) - CYP8 (A1, B1) - CYP11 (A1, B1, B2) - CYP17 (A1) - CYP19 (A1) - CYP20 (A1)
CYP21-51	CYP21 (A2) - CYP24 (A1) - CYP26 (A1, B1, C1) - CYP27 (A1, B1, C1) - CYP39 (A1) - CYP46 (A1) - CYP51 (A1)