MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion Type Simple Reactions Chemical Reactions
Reactions Classified By Substrate Small-Molecule Reactions

EC Number: (obsolete)

Enzymes and Genes:

Homo sapiens : steroid 21-monooxygenase : CYP21A2

Supersedes EC numbers:,

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

Mass balance status: Marked as unbalanced.

Enzyme Commission Primary Name: steroid 21-monooxygenase

Enzyme Commission Synonyms: steroid 21-hydroxylase, 21-hydroxylase, P450c21, CYP21A2 (gene name)

Taxonomic Range: Metazoa

Enzyme Commission Summary:
Requires NADPH and EC, NADPH--hemoprotein reductase. A heme-thiolate protein (P-450) enzyme responsible for the conversion of progesterone and 17-α-hydroxyprogesterone to their respective 21-hydroxylated derivatives, 11-deoxycorticosterone and 11-desoxycortisol. Involved in the biosynthesis of the hormones aldosterone and cortisol.

Citations: [RYAN57, Dorfman52, Plager53, Kominami80, Martineau03, Arase06]

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Unification Links: KEGG:R02130

Relationship Links: BRENDA:EC: , ENZYME:EC: , IUBMB-ExplorEnz:EC: , UniProt:RELATED-TO:P00191 , UniProt:RELATED-TO:P03940 , UniProt:RELATED-TO:P08686 , UniProt:RELATED-TO:P15540 , UniProt:RELATED-TO:Q7M366


Arase06: Arase M, Waterman MR, Kagawa N (2006). "Purification and characterization of bovine steroid 21-hydroxylase (P450c21) efficiently expressed in Escherichia coli." Biochem Biophys Res Commun 344(1);400-5. PMID: 16597434

Dorfman52: Dorfman RI, Hayano M (1952). "The action of adrenal homogenates on progesterone, 17-hydroxyprogesterone and 21-desoxycortisone." Arch Biochem Biophys 36(1);237-9. PMID: 14934270

Kominami80: Kominami S, Ochi H, Kobayashi Y, Takemori S (1980). "Studies on the steroid hydroxylation system in adrenal cortex microsomes. Purification and characterization of cytochrome P-450 specific for steroid C-21 hydroxylation." J Biol Chem 255(8);3386-94. PMID: 6767716

Martineau03: Martineau I, Belanger A, Tchernof A, Tremblay Y (2003). "Molecular cloning and expression of guinea pig cytochrome P450c21 cDNA (steroid 21-hydroxylase) isolated from the adrenals." J Steroid Biochem Mol Biol 86(2);123-32. PMID: 14568563

Plager53: Plager JE, Samuels LT (1953). "Synthesis of C14-17-hydroxy-11-desoxycorticosterone and 17-hydroxycorticosterone by fractionated extracts of adrenal homogenates." Arch Biochem Biophys 42(2);477-8. PMID: 13031650

RYAN57: RYAN KJ, ENGEL LL (1957). "Hydroxylation of steroids at carbon 21." J Biol Chem 225(1);103-14. PMID: 13416221

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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