androst-4-ene-3,17-dione + A = androsta-1,4-diene-3,17-dione + AH2
androst-4-ene-3,17-dione + a = androsta-1,4-diene-3,17-dione + ah2
androst-4-ene-3,17-dione + A = androsta-1,4-diene-3,17-dione + AH2
androst-4-ene-3,17-dione + a = androsta-1,4-diene-3,17-dione + ah2