Liver alcohol dehydrogenase (ADH1 (often "LADH" for liver-specific))

Liver alcohol dehydrogenase is a zinc-dependent oxidoreductase enzyme primarily responsible for oxidizing ethanol to acetaldehyde in the liver and other tissues[1][5][7][9]. It has a homodimeric structure with each subunit binding two zinc atoms (one catalytic, one structural)[2][5]. ADH1 also oxidizes a broad spectrum of primary and secondary alcohols and has roles in the metabolism of retinol, bile acids, and neurotransmitters[1][7]. Human liver contains three main isoforms (ADH1A, ADH1B, ADH1C) with distinct substrate affinities[6]. Variability in enzyme function—due to genetic polymorphisms—affects alcohol tolerance and disease susceptibility. The enzyme is involved in detoxifying alcohols without generating toxic radicals, unlike the cytochrome P450 system[1]. It is a key molecular target in toxicology and clinical settings, especially in treating methanol and ethylene glycol poisoning with inhibitors like fomepizole. Safety concerns arise from its central role in producing acetaldehyde, a toxic and carcinogenic intermediate, and from genetic variants that alter enzyme activity and risk profiles for alcoholism and related diseases.

Other names

Alcohol dehydrogenase 1ADH1Class I alcohol dehydrogenaseLADHMedium chain alcohol dehydrogenaseAlcohol dehydrogenase (liver)Alcohol dehydrogenase A, B, C subunits (human: ADH1A, ADH1B, ADH1C)

Oxidation of primary and secondary alcohols to corresponding aldehydes or ketones, with reduction of NAD+ to NADH - Can further oxidize aldehydes to acids (dismutation) in some cases