Divergent interactions involving the oxidosqualene cyclase and the steroid-3-ketoreductase in the sterol biosynthetic pathway of mammals and yeasts

►In NS0 cells, unlike in yeast, 3-ketoreductase does not assist oxidosqualene cyclase. ►Mouse and human 3-ketoreductases are catalytically active in yeast. ►Mouse and human 3-ketoreductases do not assist yeast oxidosqualene cyclase. ►When, from yeasts to mammals, the reductase-cyclase interaction was lost?