(Science: enzyme) An enzyme which converts androgens to oestrogens by desaturating ring a of the steroid. This enzyme complex is located in the endoplasmic reticulum of oestrogen-producing cells including ovaries, placenta, testicular sertoli and leydig cells, adipose, and brain tissues. The enzyme complex has two components, one of which is the cyp19 gene product, the aromatase cytochrome p-450. The other component is NADPH-cytochrome p-450 reductase which transfers reducing equivalents to p-450(arom).
registry number: EC 1.14.13.-