Kinetic studies of inhibition of estradiol 2- and 16 alpha-hydroxylases with 17 alpha-ethynyl and 17 beta-cyano steroids: preferential inhibition of the 16 alpha-hydroxylase.


Substrate preference of estrogen 2- and 16 alpha-hydroxylases in male rat liver microsomes were determined by using estrone (E1) and estradiol (E2). Kinetic parameters of the hydroxylations showed that E2 is a better substrate for the hydroxylations than E1 and the preferences principally depend on the differences in Vmax values of the hydroxylations… (More)