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Data from genetic crosses of Peromyscus maniculatus and P. polionotus suggests that electrophoretic variants of liver alcohol dehydrogenase are coded by alleles at a single locus. These alleles, designated AdhF, AdhS, and AdhN, determine, respectively, the fast, slow, and not detectable (null) ADH electrophoretic phenotype. Heterozygotes (AdhF/AdhS) exhibit three bands on zymograms, suggesting a dimeric subunit structure for the enzyme. However, AdhF/AdhN and AdhS/AdhN animals exhibit a single band, suggesting that the AdhN allele does not produce a polypeptide subunit capable of dimerizing into an active molecule. Fast and slow electrophoretic phenotypes exhibit multiple bands which can be converted into single major fast and slow bands, respectively, upon treatment with oxidized or reduced NAD. Addition of NAD also stabilizes both the fast and slow enzyme to heat inactivation at 60 C for at least 30 min.

Two forms of alcohol dehydrogenase (ADH), coded by allelic genes, have been purified to homogeneity from Peromyscus. Monospecific antisera to the purified enzymes have been raised in rabbits. These antisera fail to detect cross-reacting material in the liver of ADH-negative animals on Ouchterlony plates. Immuno-titration of anti-ADH antiserum with ADH in liver extracts from AdhS/AdhS and AdhS/AdhN animals results in identical equivalence points, again suggesting the absence of cross-reacting material coded by the AdhN allele. Over a wide range of anti-ADH antiserum dilutions, radiolabeled protein was not immunoprecipitable from liver extracts of AdhN/AdhN animals. These immunochemical tests, in conjunction with previous studies, suggest that the AdhN allele in Peromyscus does not produce inactive polypeptide in normal levels that bears immunological determinants similar to those of the fast and slow ADH isozymes.