Reaction catalyzed by 3alpha-hydroxysteroid 3-dehydrogenase (Si-specific) (1.1.1.50)
+
NADP+
=
+
NADPH
+
3alpha-hydroxypregn-4-en-20-one
+
NADP+
=
pregn-4-en-3,20-dione
+
NADPH
+
H+
