IUBMB Enzyme Nomenclature


Accepted name: D-xylose reductase (NADH)

Reaction: xylitol + NAD+ = D-xylose + NADH + H+

Other name(s): XYL1 (gene name) (ambiguous)

Systematic name: xylitol:NAD+ oxidoreductase

Comments: Xylose reductases catalyse the reduction of xylose to xylitol, the initial reaction in the fungal D-xylose degradation pathway. Most of the enzymes exhibit a strict requirement for NADPH (cf. EC, D-xylose reductase (NADPH)). Some D-xylose reductases have dual coenzyme specificity, though they still prefer NADPH to NADH (cf. EC, D-xylose reductase [NAD(P)H]). The enzyme from Candida parapsilosis is a rare example of a xylose reductase that significantly prefers NADH, with Km and Vmax values for NADH being 10-fold lower and 10-fold higher, respectively, than for NADPH.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Lee, J.K., Koo, B.S. and Kim, S.Y. Cloning and characterization of the xyl1 gene, encoding an NADH-preferring xylose reductase from Candida parapsilosis, and its functional expression in Candida tropicalis. Appl. Environ. Microbiol. 69 (2003) 6179-6188. [PMID: 14532079]

[EC created 2022]

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