P-450(11beta)-dependent conversion of androgen to estrogen, the aromatase reaction.

Purified bovine adrenal P-450(11)beta has been shown to act as an aromatase which catalyzes conversion of 19-oxoandrostenedione to estrone. No conversions took place when any one of the required components such as NADPH, NADPH:adrenodoxin reductase, adrenodoxin and P-450(11)beta was omitted from the complete reconstituted system. P-450scc, another mitochondrial P-450 obtained from adrenal cortex, did not substitute for the P-450(11)beta in the aromatase reaction. These results show that P-450(11)beta is able to catalyze a series of reaction which can generate adrenal estrogen through androstenedione and its 19-hydroxy- and 19-oxo-derivatives. The P-450(11)beta-dependent reaction appears to be quite different from the placental aromatase reaction in that the latter is catalyzed by a microsomal P-450.