Alcohol metabolism. Ethanol is converted to acetaldehyde by alcohol dehydrogenase (ADH) and subsequently to acetate by aldehyde dehydrogenase (ALDH). Acetate is conjugated to coenzyme A and the resulting acetyl-CoA can be metabolized in the Krebs cycle, or utilized for the synthesis of fatty acids. In addition, a small fraction of ethanol is metabolized by cytochrome P450 2E1 (CYP2E1) and in the brain by catalase. The diagram presents only those members of the ADH and ALDH families referred to in the text. Accumulation of acetaldehyde is responsible for the physiological malaise commonly known as 'hangover'.