The differences in the amino acid sequences encoded by the various ADH1B and ADH1C alleles lead to differences in the predicted rates of ethanol metabolism in the liver. Based on the kinetic properties of the different variants and the estimated ADH enzyme content in liver, researchers have calculated the contribution of the different ADH enzymes to the liver’s ability to oxidize ethanol. These calculations typically are based on a 70-kg man who has a blood alcohol concentration (BAC) of approximately 100 mg/100 mL (0.1 percent, corresponding to approximately 22 mM ethanol, a level that is legally considered intoxicating). If the man carries two copies each of the “reference” ADH1B*1 and ADH1C*1 alleles5 (i.e., is homozygous for ADH1B*1 and ADH1C*1), the class I enzymes (that is, homo- and heterodimers of α-, β-, and γ-ADH) together account for approximately 70 percent of the liver’s total ethanol-oxidizing capacity; in addition, π-ADH accounts for nearly 30 percent (Hurley et al. 2002). The ethanol-oxidizing capacities of men with the same weight and BAC, but with different ADH1B and ADH1C alleles, also have been estimated (Lee
