Three taxonomically different human gut bacterial families of Erysipelotrichaceae, Burkholderiaceae, and Eggerthellaceae with an arsenal of respiratory-like reductase enzymes in tens to hundreds ...

The listing of more than one enzyme indicates a multistep process ... KSR = ketosteroid reductase, R = reductase, scc = side-chain cleavage, SH = sulfohydrolase, P-S = pregnenolone sulfate ...