[delta 1-steroid-dehydrogenase biosynthesis and androsta-4-ene-3,17-dione degradation by "Nocardia restricta" (author's transl)].

The acetate, hexanoate and glucose catabolisms have not repressing influence on androsta-4-ene-3,17-dione induced delta 1-steroid-dehydrogenase in Nocardia restricta during the growth on synthetic media. Methyl-perhydroindane-dione-propionic acid degradation is a limiting step of the androsta-4-ene-3,17-dione catabolism on acetate medium. On this medium induction of delta 1-steroid-dehydrogenase synthesis takes place in two steps: a first inducer is androsta-4-ene-3,17-dione; a second inducer is a so far undefined product of methyl-perhydroindane-dione-propionic acid catabolism, On hexanoate medium, during androsta-4-ene-3,17-dione degradation, this acid does not accumulate, and the synthesis of delta 1-steroid-dehydrogenase is then only induced by androsta-4-ene-3,17-dione. The degradation of this steroid on acetate at pH below 7,0 gives, with a 50% yield, 3-hydroxy-9(10)-seco-androsta-1,3,5(10)-triene-9,17-dione.