Further purification and characterization of diacetyl reducing enzymes from beef liver.

Two diacetyl reducing enzymes have been isolated from beef liver. One of them, a monomer of mol. wt 28-30,000 dalton and pI 6.2, corresponds to the low molecular weight diacetyl reductase formerly accounted for using preparations of this organ; it has been now identified as an L-glycol dehydrogenase. The other one, an oligomer of 78,000 dalton and pI 7.0, which matches the high molecular weight diacetyl reductase, is, in the authors' opinion, a new enzyme for which the systematic name L(+)-alpha-hydroxycarbonyl: NAD(P) oxidoreductase (EC 1.1.1...) and common name alpha-dicarbonyl reductase are proposed.