Catalyzes the NAD(+)-dependent oxidation of the hydroxyl group at C3 of D-gulosides leading to 3-dehydro-D-gulosides. Probably functions in a metabolic pathway that transforms D-gulosides to D-glucosides. Is also able to catalyze the reverse reactions, i.e. the NADH-dependent reduction of the oxo group at C3 of 3-dehydro-D-gulosides leading to D-gulosides. In vitro, can oxidize D-gulose and methyl beta-D-guloside, and reduce methyl alpha-3-dehydro-D-guloside and methyl beta-3-dehydro-D-guloside. However, the actual specific physiological substrates for this metabolic pathway are unknown. a D-guloside + NAD(+) = a 3-dehydro-D-guloside + H(+) + NADH Binds 1 Zn(2+) ions per subunit. kcat is 0.18 sec(-1) for the NAD(+)-dependent oxidation of D-gulose (at pH 8.0 and 30 degrees Celsius). kcat is 0.23 sec(-1) for the NAD(+)-dependent oxidation of D-gulose (at pH 9.0 and 30 degrees Celsius). kcat is 0.35 sec(-1) for the NAD(+)-dependent oxidation of methyl beta-D-guloside (at pH 8.0 and 30 degrees Celsius). kcat is 1.2 sec(-1) for the NAD(+)-dependent oxidation of methyl beta-D-guloside (at pH 9.0 and 30 degrees Celsius). kcat is 18.5 sec(-1) for the NADH-dependent reduction of methyl alpha-3-dehydro-D-guloside (at pH 7.0 and 30 degrees Celsius). kcat is 3.8 sec(-1) for the NADH-dependent reduction of methyl alpha-3-dehydro-D-guloside (at pH 8.0 and 30 degrees Celsius). kcat is 7.0 sec(-1) for the NADH-dependent reduction of methyl beta-3-dehydro-D-guloside (at pH 7.0 and 30 degrees Celsius). kcat is 9.7 sec(-1) for the NADH-dependent reduction of methyl beta-3-dehydro-D-guloside (at pH 8.0 and 30 degrees Celsius). Belongs to the zinc-containing alcohol dehydrogenase family.