[19-14C]Androstenedione has been prepared and utilized as a substrate for assaying microsomal human placental aromatase. Enzyme activity is determined by measuring the rate at which [14C]formate is produced by aromatization of this 14C-labeled steroid. Isotope ratio experiments using [19-14C]androstenedione and [1β-3H]androstenedione demonstrate that an apparent kinetic hydrogen isotope effect exists for the aromatization of the tritiated steroid with kH/kT ≈ 1.09. Metabolic switching occurs to a minor extent (≈3%) during aromatization of [1β-3H]androstenedione, but not during the aromatization of [19-14C]androstenedione.
|Number of pages||6|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Nov 30 1988|