1,6-dihydro-NAD as an humidity-induced lactate dehydrogenase inhibitor in NADH preparations

Abstract

An authentic mixture of 1,2-, 1,4- and 1,6-dihydro-NAD was characterized by high pressure liquid chromatography. Pure 1,6-dihydro-NAD isolated from this mixture was shown to be a potent inhibitor of lactate dehydrogenase and to exhibit an UV spectrum identical to that of an extensively purified lactate dehydrogenase inhibitor generated by exposing NADH to moisture. The humidity induced inhibitor, which could not be separated from NADH by DEAE chromatography, cochromatographed with 1,6-dihydro-NAD during both DEAE and high pressure liquid chromatography and is therefore presumably identical to 1,6-dihydro-NAD. © 1978 Carlsberg Laboratory.