estriol, SULT2B1, 22.214.171.124, 126.96.36.199, 188.8.131.52, Estrone-3 sulfate, HSD17B8, HSD17B7, 184.108.40.206, Estrone, 220.127.116.11, 18.104.22.168, 22.214.171.124, 16beta-3,16- Dihydroxy-estra- 1,3,5-trien-17-one, 126.96.36.199, COMT, 16alpha-3,16- Dihydroxy-estra-1,3,5-trien-17-one, CYP2C19, 4-Hydroxyestrone, HSD17B2, 188.8.131.52, 3,4-dihydroxy-Estra-1,3,5-trien-17-one 4-methyl ether, CYP1A2, STS, HSD17B3, 2,3-dihydroxy-Estra-1,3,5-trien-17-one 2-methyl ether sulfate, 184.108.40.206, 2-Hydroxyestrone, 2,3-dihydroxy-Estra-1,3,5-trien-17-one 2-methyl ether, HSD17B1, CYP2C9, CYP3A5, 220.127.116.11, SULT1E1, CYP3A4
Endogenous and exogenous estrogens undergo oxidative metabolism by hepatic microsomal cytochrome P-450. Aromatic hydroxylation at either the C2 or C4 position is a major route of Estrone metabolism in humans and other mammals, although there are less 4-hydroxylation than 2-hydroxylation events.
Several cytochrome P450 isoforms including Cytochrome P450, family 2, subfamily C, polypeptide 9 ( CYP2C9 ), Cytochrome P450, family 3, subfamily A, polypeptides 4 ( CYP3A4 ) and 5 ( CYP3A5 ), Cytochrome P450, family 1, subfamily A, polypeptide 2 ( CYP1A2 ), and Cytochrome P450, family 2, subfamily C, polypeptide 19 ( CYP2C19 )  catalyze the hydroxylation of Estrone to 2-Hydroxyestrone or/and 4-Hydroxyestrone. Further, Catechol-O-methyltransferase ( COMT ) catalyzes the methylation of 2-Hydroxyestrone and 4-Hydroxyestrone to corresponding 2-Methoxyestrone and 4-Metoxyestrone .
CYP3A4 , , CYP3A5 , , and CYP2C19  also catalyze 16alpha-hydroxylation of Estrone forming 16alpha-Hydroxyestrone. 16-Hydroxysteroid epimerase converts 16alpha-Hydroxyestrone to 16beta-Hydroxyestrone .
16alpha-Hydroxyestrone is also formed via Estriol oxidation by Hydroxysteroid (17-beta) dehydrogenases 1, 2, 3, 7 and 8 ( HSD17B1, HSD17B2, HSD17B3, HSD17B7 and HSD17B8).
Sulfotransferase family 1E, estrogen-preferring, member 1 ( SULT1E1 )  catalyzes sulfation of Estrone to Estrone 3-sulfate. Reverse reaction, the hydrolysis of Estrone 3-sulfate, is catalyzed by Steroid sulfatase (microsomal), isozyme S ( STS ) .