Reduces acetaldehyde to ethanol during glucose fermentation. Specific for ethanol. Shows drastically reduced activity towards primary alcohols from 4 carbon atoms upward. Isomers of aliphatic alcohol, as well as secondary alcohols and glycerol are not used at all. a primary alcohol + NAD(+) = an aldehyde + H(+) + NADH ethanol + NAD(+) = acetaldehyde + H(+) + NADH Zinc. May bind iron when zinc levels are limiting. Inhibited by EDTA. Optimum pH is 8.3. Homodimer. Induced by transcription factor ZAP1 in response to zinc deficiency. While ADH4 is expressed at only low levels in laboratory strains, it is often highly expressed in brewing strains. Present with 125 molecules/cell in log phase SD medium. Belongs to the iron-containing alcohol dehydrogenase family.