LDHA and alcohol abuse: Alcohol use disorders have led to extensive research on alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes in the body. In healthy individuals, ADH is the primary enzyme involved in the breakdown of ethanol in acetaldehyde and ALDH, which responsible for breaking down acetaldehyde to acetate which is a harmless substance which can be further metabolized and eliminated by the body.