Sethumadhavan K, Bellino FL, Thotakura NR. Estrogen synthetase (aromatase). The cytochrome P-450 component of the human placental enzyme is a glycoprotein.
Mol Cell Endocrinol 1991;
78:25-32. [PMID:
1936523 DOI:
10.1016/0303-7207(91)90182-r]
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Abstract
Estrogen synthetase (aromatase) is a cytochrome P-450 enzyme system which converts androgens to estrogens. Although this enzyme has been purified and the cDNA-derived amino acid sequence elucidated, very little is known regarding post-translational modifications of this physiologically crucial enzyme. We show here that the cytochrome P-450 component, P-450ES, purified from human term placental microsomes, is a glycoprotein based on the following evidence: its molecular weight is decreased following treatment with endoglycosidase F, concanavalin A-biotin specifically binds to this protein immobilized on nitrocellulose, and its oligosaccharide composition is consistent with a single N-linked fucosylated complex type carbohydrate chain. In a reconstitution system, the aromatase activity using the endoglycosidase F-treated P-450ES was reduced by about 35-40% relative to the native form, regardless of whether androstenedione or testosterone was used as substrate.
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