ExplorEnz: EC 1.14.14.14

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1.14.14.14

Accepted name:

aromatase

Reaction:

(1) testosterone + 3 O₂ + 3 [reduced NADPH—hemoprotein reductase] = 17β-estradiol + formate + 4 H₂O + 3 [oxidized NADPH—hemoprotein reductase] (overall reaction)
(1a) testosterone + O₂ + [reduced NADPH—hemoprotein reductase] = 19-hydroxytestosterone + H₂O + [oxidized NADPH—hemoprotein reductase]
(1b) 19-hydroxytestosterone + O₂ + [reduced NADPH—hemoprotein reductase] = 19-oxotestosterone + 2 H₂O + [oxidized NADPH—hemoprotein reductase]
(1c) 19-oxotestosterone + O₂ + [reduced NADPH—hemoprotein reductase] = 17β-estradiol + formate + H₂O + [oxidized NADPH—hemoprotein reductase]
(2) androst-4-ene-3,17-dione + 3 O₂ + 3 [reduced NADPH—hemoprotein reductase] = estrone + formate + 4 H₂O + 3 [oxidized NADPH—hemoprotein reductase] (overall reaction)
(2a) androst-4-ene-3,17-dione + O₂ + [reduced NADPH—hemoprotein reductase] = 19-hydroxyandrost-4-ene-3,17-dione + H₂O + [oxidized NADPH—hemoprotein reductase]
(2b) 19-hydroxyandrost-4-ene-3,17-dione + O₂ + [reduced NADPH—hemoprotein reductase] = 19-oxo-androst-4-ene-3,17-dione + 2 H₂O + [oxidized NADPH—hemoprotein reductase]
(2c) 19-oxoandrost-4-ene-3,17-dione + O₂ + [reduced NADPH—hemoprotein reductase] = estrone + formate + H₂O + [oxidized NADPH—hemoprotein reductase]

Other name(s):

CYP19A1 (gene name); estrogen synthetase (incorrect)

Systematic name:

testosteronel,NADPH—hemoprotein reductase:oxygen oxidoreductase (17β-estradiol-forming)

Comments:

A cytochrome P-450. The enzyme catalyses three sequential hydroxylations of the androgens androst-4-ene-3,17-dione and testosterone, resulting in their aromatization and forming the estrogens estrone and 17β-estradiol, respectively. The direct electron donor to the enzyme is EC 1.6.2.4, NADPH—hemoprotein reductase.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Thompson, E.A., Jr. and Siiteri, P.K. The involvement of human placental microsomal cytochrome P-450 in aromatization. J. Biol. Chem. 249 (1974) 5373–5378. [PMID: 4370479]
2.	Fishman, J. and Goto, J. Mechanism of estrogen biosynthesis. Participation of multiple enzyme sites in placental aromatase hydroxylations. J. Biol. Chem. 256 (1981) 4466–4471. [PMID: 7217091]
3.	Kellis, J.T., Jr. and Vickery, L.E. Purification and characterization of human placental aromatase cytochrome P-450. J. Biol. Chem. 262 (1987) 4413–4420. [PMID: 3104339]
4.	Ghosh, D., Griswold, J., Erman, M. and Pangborn, W. Structural basis for androgen specificity and oestrogen synthesis in human aromatase. Nature 457 (2009) 219–223. [DOI] [PMID: 19129847]

[EC 1.14.14.14 created 2013]