Catalyzes the NAD(+)-dependent oxidation of scyllo-inosose (2-keto-myo-inositol) to 3-dehydro-scyllo-inosose (diketo-inositol), and thus probably functions in a myo-inositol degradation pathway together with IolG, IolN and IolO. Has no activity on myo-inositol, D-chiro-inositol and 1-keto-D-chiro-inositol. NAD(+) + scyllo-inosose = 3-dehydro-scyllo-inosose + H(+) + NADH Binds 2 Zn(2+) ions per subunit. kcat is 1 sec(-1). Polyol metabolism; myo-inositol metabolism. Homodimer. Belongs to the zinc-containing alcohol dehydrogenase family.