Alcohol dehydrogenase catalyses the reaction: RCH₂OH +NAD⁺ → RCHO + NADH + H⁺. It facilitates the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+ to NADH). In biotransformation, alcohol dehydrogenases are often used for the synthesis of enantiomerically pure stereoisomers of chiral alcohols.