Enzyme-generated intermediates derived from 4-andr0stene-3, 6, 17-tri0ne and 1, 4, 6-androstatriene-3, 17-di0ne cause a time-dependent decrease in human placental aromatase activity

Douglas F. Covey, William F. Hood

Research output: Contribution to journalArticle

107 Scopus citations

Abstract

Kinetic evidence is presented for a time-dependent decrease in human placental aromatase activity by enzyme-generated intermediates derived from two widely used steroids previously described as competitive inhibitors of estrogen biosynthesis. Thus, 4-androstene-3, 6, 17-trione binds to the enzyme with an apparent of 0.43 pM and has a pseudo-first order overall rate constant for decrease in activity of 4.03×10-3sec-1 while 1, 4, 6-androstatriene-3, 17-dione has an apparent Kii of 0.18 μM and a pseudo-first order overall rate constant for decrease in activity of 1.10×10-3sec-1. These findings imply that the potent inhibition of estrogen biosynthesis caused by these steroids results primarily from a decrease in enzyme activity caused by enzyme–generated intermediates derived from the parent steroids.

Original languageEnglish
Pages (from-to)1597-1599
Number of pages3
JournalEndocrinology
Volume108
Issue number4
DOIs
StatePublished - Apr 1981

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