a 3-oxo-5beta-steroid + A => a 3-oxo-Delta(4)-steroid + AH2
a 3-oxo-5beta-steroid + a => a 3-oxo-delta(4)-steroid + ah2
a 3-oxo-5beta-steroid + A => a 3-oxo-Delta(4)-steroid + AH2
a 3-oxo-5beta-steroid + a => a 3-oxo-delta(4)-steroid + ah2