Polyol dehydrogenase that catalyzes the reversible NAD(+)-dependent oxidation of various sugar alcohols. Is mostly active with xylitol, D-sorbitol (D-glucitol) and L-iditol as substrates, leading to the C2-oxidized products D-xylulose, D-fructose and L-sorbose, respectively (PubMed:9143345). 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). Cannot use NADP(+) as the electron acceptor. Has no activity on ethanol, methanol, glycerol, galactitol and fructose 6-phosphate (PubMed:9143345). NAD(+) + xylitol = D-xylulose + H(+) + NADH H(+) + keto-D-fructose + NADH = D-sorbitol + NAD(+) L-iditol + NAD(+) = H(+) + keto-L-sorbose + NADH Binds 1 zinc ion per subunit. Inhibited in vitro by metal chelators such as EDTA and 1,10-phenanthroline. kcat is 29 sec(-1) for D-sorbitol oxidation (at pH 8.0). kcat is 26 sec(-1) for xylitol oxidation (at pH 8.0). kcat is 21 sec(-1) for L-iditol oxidation (at pH 8.0). kcat is 22 sec(-1) for ribitol oxidation (at pH 8.0). kcat is 24 sec(-1) for D-mannitol oxidation (at pH 8.0). kcat is 12 sec(-1) for L-threitol oxidation (at pH 8.0). kcat is 162 sec(-1) for D-fructose reduction (at pH 7.4). kcat is 153 sec(-1) for L-sorbose reduction (at pH 7.4). kcat is 198 sec(-1) for D-ribulose reduction (at pH 7.4). Optimum pH is about 9 for D-sorbitol oxidation, and 7.4 for D-fructose reduction. Homotetramer. 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 lens. Belongs to the zinc-containing alcohol dehydrogenase family.