Enzymatic aromatization of steroids. I. Effects of oxygen and carbon monoxide on the intermediate steps of estrogen biosynthesis.

摘要: Intermediate steps in the aromatization of 4-androstene-3,17-dione to estrone, catalyzed by human placental microsomes, have been evaluated through use normal and hypothetical intermediate compounds as substrates oxidases involved characterized effects oxygen carbon monoxide upon these conversions. When air was replaced a 5% oxygen-95% nitrogen atmosphere, rate or 19-hydroxy-4-androstene-3,17-dione reduced 30 35% while no inhibition occurred if 3,17-dioxo-4-androsten-19-al substrate. The all three steroids not inhibited when added at concentration 8.8 times that oxygen. However, this same CO:O2 ratio decreased 4-estrene-3,17-dione 51 95% 1,4-androstadiene-3,17-dione 10 16%. Hydroxylation A ring also extent its aromatization. These findings interpreted evidence for existence mixed function active steroid aromatization, one which may be form cytochrome P-450.