Sorbitol dehydrogenase is an NAD(+) binding protein of the polyol pathway, which interconverts glucose and fructose. Sorbitol dehydrogenase is tetrameric and has a single catalytic zinc per subunit []. Proteins in this entry also includes D-xylulose reductases and L-arabinitol 4-dehydrogenases from fungi, such as XdhA from Aspergillus oryzae and Lad1 from Hypocrea jecorina. XdhA catalyses the conversion of xylitol to D-xylulose. Xylose is a major component of hemicelluloses such as xylan []. Lad1 catalyses the NAD-dependent oxidation of L-arabinitol to L-xylulose in the fungal L-arabinose catabolic pathway [].
