The 'true' L-xylulose reductase of filamentous fungi identified in Aspergillus niger.

Dominik Mojzita, Kiira Vuoristo, Outi M Koivistoinen, Merja Penttilä, Peter Richard

Index: FEBS Lett. 584(16) , 3540-4, (2010)

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Abstract

L-Xylulose reductase is part of the eukaryotic pathway for l-arabinose catabolism. A previously identified L-xylulose reductase in Hypocrea jecorina turned out to be not the 'true' one since it was not upregulated during growth on L-arabinose and the deletion strain showed no reduced L-xylulose reductase activity but instead lost the D-mannitol dehydrogenase activity. In this communication we identified the 'TRUE'L-xylulose reductase in Aspergillus niger. The gene, lxrA (JGI177736), is upregulated on L-arabinose and the deletion results in a strain lacking the NADPH-specific L-xylulose reductase activity and having reduced growth on l-arabinose. The purified enzyme had a K(m) for L-xylulose of 25 mM and a nu(max) of 650 U/mg.Copyright 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.