Aromatase (cytochrome P450 19A1) (CYP19A1)

Aromatase is a cytochrome P450 monooxygenase encoded by the CYP19A1 gene. It catalyzes the conversion of C19 androgens (androstenedione, testosterone) into C18 estrogens (estrone, estradiol) via a three-step oxidation and aromatization mechanism. This enzyme is the only known vertebrate enzyme capable of aromatizing the steroid A-ring, making it essential in estrogen synthesis[1][4][8]. Expressed in multiple tissues—including gonads, adipose tissue, placenta, brain, and breast—aromatase regulates estrogen production critical for sexual development and reproductive function. Its overexpression is implicated in hormone-dependent breast cancer, providing a frontline therapeutic target for aromatase inhibitors, which reduce estrogen levels by inhibiting aromatase-mediated biosynthesis[2][5][7][8].

Other names

estrogen synthetaseestrogen synthaseCYP19CYP19A1

Competitive inhibition (non-steroidal inhibitors: reversible binding at the active site, e.g., anastrozole, letrozole)[3][6] Mechanism-based (suicide) inhibition (steroidal inhibitors form covalent bonds, irreversibly inactivating aromatase, e.g., exemestane)[3][6]