Able to catalyze the elimination of the C-1 and C-2 hydrogen atoms of the A-ring from the polycyclic ring structure of 3-ketosteroids, but the ketosteroid dehydrogenase activity is low compared to KsdD in the cholesterol degradation process. The low activity could be due to different substrate specificity. Lipid metabolism; steroid biosynthesis. Cells accumulate a small amount of 4-androstene-3,17-dione (AD) and 9alpha-hydroxy-4-androstene-3,17-dione (9OHAD) in the first 24-48 hours of cholesterol degradation process. Belongs to the FAD-dependent oxidoreductase 2 family.