THE FATE OF CARBON-19 IN THE COURSE OF OESTROGEN BIOSYNTHESIS FROM TESTOSTERONE-19-14C

Abstract

ABSTRACT Testosterone-19-14C was incubated with various fractions obtained from placental homogenates. Radioactive formic acid was the major product, and under certain conditions radioactive formaldehyde was also formed. Chemical analysis of formic acid and formaldehyde did not correspond quantitatively with the amount of these radioactive compounds formed. Magnesium and tetrahydrofolic acid were found to inhibit the reaction partially and cyanide produced virtually complete inhibition. Radioactive CO2 was found to be a minor product of the overall reaction. Analysis of methionine, serine and various intermediates of the tetrahydrofolic acid cycle showed that this pathway is not involved in the immediate removal of carbon-19.