Human Aromatase

Abstract

Aromatase, a cytochrome P-450, catalyzes the formation of aromatic C18 steroids from C19 androgens. The conversion reaction consists of complex processes which involve oxidative removal of the angular C-19 methyl group as formic acid and subsequent aromatization of the A ring (Fig. 1). Three moles each of NADPH and O₂ are consumed for each mole of estrogen formed. This enzyme has received considerable attention because of the central importance of estrogens in many reproductive and metabolic processes. A more detailed understanding of the role of this enzyme in steroidgenic metabolism has necessitated characterization of the protein at a molecular level.