This isozyme preferentially catalyzes the conversion of ethanol to acetaldehyde. Acts on a variety of primary unbranched aliphatic alcohols. a primary alcohol + NAD(+) = an aldehyde + H(+) + NADH a secondary alcohol + NAD(+) = a ketone + H(+) + NADH Binds 2 Zn(2+) ions per subunit. Homotetramer. Repressed by glucose. Present with 1620 molecules/cell in log phase SD medium. Belongs to the zinc-containing alcohol dehydrogenase family.