Polyol dehydrogenase that catalyzes the reversible NAD(+)-dependent oxidation of various sugar alcohols (By similarity). Is active with D-sorbitol (D-glucitol) leading to the C2-oxidized product D-fructose (PubMed:6862079). Is a key enzyme in the polyol pathway that interconverts glucose and fructose via sorbitol, which constitutes an important alternate route for glucose metabolism. May play a role in sperm motility by using sorbitol as an alternative energy source for sperm motility (By similarity). H(+) + keto-D-fructose + NADH = D-sorbitol + NAD(+) NAD(+) + xylitol = D-xylulose + H(+) + NADH L-iditol + NAD(+) = H(+) + keto-L-sorbose + NADH Binds 1 zinc ion per subunit. kcat is 8 sec(-1) for sorbitol oxidation and 190 sec(-1) for D-fructose reduction. Homotetramer; dimer of dimers. Associated with mitochondria of the midpiece and near the plasma membrane in the principal piece of the flagellum. Also found in the epididymosome, secreted by the epididymal epithelium and that transfers proteins from the epididymal fluid to the sperm surface. Expressed in liver and testis. Consists of two distinct domains, a catalytic domain and a coenzyme-binding domain. Belongs to the zinc-containing alcohol dehydrogenase family. PubMed:8223590 reports a cDNA predicted to encode a protein with an extended N-terminus but there is no further evidence for the existence of such a protein. Extended N-terminus.