{{infokutija gen}}
</ref><ref name="pmid28677294">{{cite journal | vauthors = Kaewkot A, Boonkaewwan C, Noosud J, Kayan A | title = Expression level of the cytochrome P450c21 (CYP21) protein correlating to drip loss in pigs | journal = Animal Science Journal | volume = 88 | issue = 11 | pages = 1855–1859 | date = novembar 2017 | pmid = 28677294 | doi = 10.1111/asj.12863 | url = }}</ref><ref name="pmid21446712">{{cite journal | vauthors = Mizrachi D, Wang Z, Sharma KK, Gupta MK, Xu K, Dwyer CR, Auchus RJ | title = Why human cytochrome P450c21 is a progesterone 21-hydroxylase | journal = Biochemistry | volume = 50 | issue = 19 | pages = 3968–74 | date = maj 2011 | pmid = 21446712 | pmc = 3165045 | doi = 10.1021/bi102078e | url = }}</ref> steroid 21-monooksigenaza,<ref>{{cite web |url=https://www.brenda-enzymes.org/enzyme.php?ecno=1.14.14.16 |title=Information on EC 1.14.14.16 - steroid 21-monooxygenase}}</ref> 21-hidroksilaza, 21α-hidroksilaza,<ref name="pmid31839646">{{cite journal | vauthors = Mukangwa M, Takizawa K, Aoki Y, Hamano S, Tetsuka M | title = Expression of genes encoding mineralocorticoid biosynthetic enzymes and the mineralocorticoid receptor, and levels of mineralocorticoids in the bovine follicle and corpus luteum | journal = The Journal of Reproduction and Development | volume = 66 | issue = 1 | pages = 75–81 | date = februar 2020 | pmid = 31839646 | pmc = 7040213 | doi = 10.1262/jrd.2019-127 }}</ref><ref name="pmid21534945">{{cite journal | vauthors = Sarafoglou K, Lorentz CP, Otten N, Oetting WS, Grebe SK | title = Molecular testing in congenital adrenal hyperplasia due to 21α-hydroxylase deficiency in the era of newborn screening | journal = Clinical Genetics | volume = 82 | issue = 1 | pages = 64–70 | date = juli 2012 | pmid = 21534945 | doi = 10.1111/j.1399-0004.2011.01694.x | s2cid = 7197547 }}</ref> 21β-hidroksilaza<ref name="pmid16540460">{{cite journal | vauthors = Bergamaschi R, Livieri C, Uggetti C, Candeloro E, Egitto MG, Pichiecchio A, Cosi V, Bastianello S | title = Brain white matter impairment in congenital adrenal hyperplasia | journal = Archives of Neurology | volume = 63 | issue = 3 | pages = 413–6 | date = mart 2006 | pmid = 16540460 | doi = 10.1001/archneur.63.3.413| doi-access = free }}</ref><ref name="pmid14640134">{{cite journal | vauthors = Marcol W, Kalina-Faska B, Wackermann-Ramos A, Koehler B | title = Congenital adrenal hyperplasia conditioned by 21beta-hydroxylase deficiency - clinical considerations | language = pl | journal = Endokrynologia, Diabetologia I Choroby Przemiany Materii Wieku Rozwojowego | volume = 6 | issue = 1 | pages = 67–9 | date = 2000 | pmid = 14640134}}</ref>
| EC_number = {{wikidata|property|P591}}
| CAS_number = {{wikidata|property|P231}}
| IUBMB_EC_number = 1/14/99/10
| GO_code = 0004509
| image = {{wikidata|property|raw|P18}}
| caption = {{wikidata|qualifier|P4896|P2096}}
| name = Steroidna 21-hidroksilaza}}
'''Steroid 21-hidroksilaza''', znana i kao  '''citohrom P450c21''', '''steroid 21-monooksigenaza''', '''21α-hidroksilaza''' i, manje uobičajeno, '''21β-hidroksilaza''', jest [[enzim]] koji je kod [[ljudi]] [[kodon|kodiran]] [[gen]]om '''CYP21A2'''.  [[Hidroksilacija|Hidroksilira]] [[steroid]]e na poziciji  C21<ref name="ncbi">{{cite web |url=https://www.ncbi.nlm.nih.gov/gene/1589 |title=NCBI: CYP21A2 cytochrome P450 family 21 subfamily A member 2 | publisher = National Center for Biotechnology Information | access-date = 30. 11. 2020|quote=This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and hydroxylates steroids at the 21 position. Its activity is required for the synthesis of steroid hormones including cortisol and aldosterone. Mutations in this gene cause congenital adrenal hyperplasia. A related pseudogene is located near this gene; gene conversion events involving the functional gene and the pseudogene are thought to account for many cases of steroid 21-hydroxylase deficiency. Two transcript variants encoding different isoforms have been found for this gene.}}</ref><ref name="pmid13416221">{{cite journal | vauthors = Ryan KJ, Engel LL | title = Hydroxylation of steroids at carbon 21 | journal = The Journal of Biological Chemistry | volume = 225 | issue = 1 | pages = 103–14 | date = mart 1957 | doi = 10.1016/S0021-9258(18)64913-0 | pmid = 13416221 | url = http://www.jbc.org/content/225/1/103.full.pdf | doi-access = free }}</ref> i uključen je u [[biosinteza|biosintezu]] [[aldosteron]]a i [[kortizol]]a. Enzim pretvara [[progesteron]] i [[17α-hidroksiprogesteron]] u [[11-deoksikortikosteron]] i [[11-deoksikortizol]]<ref name="Pallan_2015">{{cite journal | vauthors = Pallan PS, Wang C, Lei L, Yoshimoto FK, Auchus RJ, Waterman MR, Guengerich FP, Egli M | title = Human Cytochrome P450 21A2, the Major Steroid 21-Hydroxylase: structure of the enzyme progesterone substrate complex and rate-limiting c-h bond cleavage | journal = The Journal of Biological Chemistry | volume = 290 | issue = 21 | pages = 13128–43 | date = maj 2015 | pmid = 25855791 | pmc = 4505568 | doi = 10.1074/jbc.M115.646307 | doi-access = free }}</ref><ref name="pmid28065637">{{cite journal | vauthors = Neunzig J, Milhim M, Schiffer L, Khatri Y, Zapp J, Sánchez-Guijo A, Hartmann MF, Wudy SA, Bernhardt R | display-authors = 6 | title = The steroid metabolite 16(β)-OH-androstenedione generated by CYP21A2 serves as a substrate for CYP19A1 | journal = The Journal of Steroid Biochemistry and Molecular Biology | volume = 167 | pages = 182–191 | date = mart 2017 | pmid = 28065637 | doi = 10.1016/j.jsbmb.2017.01.002 | s2cid = 36860068 }}</ref> unutar [[metabolički put|metaboličkih puteva]] koji na kraju dovode do [[aldosteron]]a i [[kortizol]]a. Nedostatak enzima može uzrokovati [[Kongenitalna adrenalna hiperplazija zbog nedostatka 21-hidroksilaze|urođenu nadbubrežnu hiperplaziju]].