Cytochrome P450 19A1 (Aromatase) (CYP19A1)

Cytochrome P450 19A1, commonly known as aromatase, is the enzyme responsible for the rate-limiting step in estrogen biosynthesis (UniProt P11511). It catalyzes the aromatization of androgens, such as testosterone and androstenedione, into estrogens like estradiol and estrone (NCBI Gene: 1588). This enzyme is expressed in various tissues, including the ovaries, adipose tissue, brain, and placenta. In postmenopausal women, aromatase activity in peripheral tissues is the primary source of circulating estrogens (StatPearls: Aromatase Inhibitors). Because many breast cancers are estrogen-receptor positive and depend on estrogen for proliferation, aromatase is a major therapeutic target in oncology. Drugs like anastrozole act as potent, non-steroidal inhibitors of this enzyme, effectively lowering systemic estrogen levels to treat hormone-sensitive malignancies (PubChem CID 2199). Beyond cancer, aromatase is involved in maintaining bone density, regulating lipid metabolism, and influencing sexual behavior.

Other names

AromataseEstrogen synthaseCYP19P450AROMCytochrome P450, family 19, subfamily A, polypeptide 1CYP19A1

Aromatase inhibitors bind to the heme group of the cytochrome P450 19A1 enzyme, either reversibly (non-steroidal inhibitors like anastrozole) or irreversibly (steroidal inhibitors like exemestane), to block the conversion of androgens into estrogens (StatPearls: Aromatase Inhibitors).