THE PRODUCTION AND PROPERTIES OF A NEW XYLOSE REDUCTASE FROM FUNGUS -NEUROSPORA-CRASSA

Neurospora crassa X1 was found to ferment xylose and glucose simultane ously. Xylose was the appropriate inducer for the production of xylose reductase that had two isoenzymes designated as EI and EII. Both EI a nd EII, which were purified by affinity chromatography, had NADPH-depe ndent xylose reductase activities. EII also had NADH-dependent activit y, and EI is the only xylose reductase found so far without any NADH-d ependent activity. EI and EII had MWs of 30 kDa and 27 kDa, and pls of 5.6 and 5.2, respectively. The specifities of EI and EII against trio se, pentoses, and hexoses were studied. The K(m)s against xylose for E I and EII were 2.3 mM and 1.1 mM respectively, which were much lower t han those of the xylose reductase from yeast.