Class-III ADH is remarkably ineffective in oxidizing ethanol, but it readily catalyzes the oxidation of long-chain primary alcohols and the oxidation of S-(hydroxymethyl) glutathione. a primary alcohol + NAD(+) = an aldehyde + H(+) + NADH a secondary alcohol + NAD(+) = a ketone + H(+) + NADH NADP(+) + S-(hydroxymethyl)glutathione = H(+) + NADPH + S-formylglutathione NAD(+) + S-(hydroxymethyl)glutathione = H(+) + NADH + S-formylglutathione Binds 2 Zn(2+) ions per subunit. Homodimer. Belongs to the zinc-containing alcohol dehydrogenase family. Class-III subfamily.