Acts equally well on hydrated NADH and hydrated NADPH. NAD(P)H spontaneously hydrates to both the (6S)- and (6R)- isomers. The enzyme from bacteria consists of two domains, one of which acts as an NAD(P)H-hydrate epimerase that interconverts the two isomers to a 60:40 ratio (cf. EC?5.1.99.6), while the other catalyses the dehydration. Hence the enzyme can restore the complete mixture of isomers into NAD(P)H. The enzyme has no activity with ATP, contrary to the enzyme from eukaryotes (cf. EC?4.2.1.93, ATP-dependent NAD(P)H-hydrate dehydratase).