Wheat Alcohol Dehydrogenase Isozymes: PURIFICATION, CHARACTERIZATION, AND GENE EXPRESSION

Evidence in support of the hypothesis of gene expression and subunit association suggested earlier for Triticum alcohol dehydrogenase has been obtained through purification and partial characterization of the enzyme from tetraploid wheat. Three isozymes of alcohol dehydrogenase were separated and purified to apparent homogeneity using streptomycin sulfate precipitation, gel filtration chromatography, and anion exchange chromatography. The isozymes are dimers with the same molecular weight (116,000 +/- 2,000), but significantly different isoelectric pH values. The Michaelis constants for NAD(+) and ethanol are 0.1 millimolar and 12 millimolar, respectively. The substrate specificity of the three alcohol dehydrogenase isozymes was investigated.