MULTIPLE FORMS OF THE CONSTITUTIVE WHEAT CINNAMYL ALCOHOL-DEHYDROGENASE

Three cinnamyl alcohol dehydrogenase (CAD) isoenzymes were separated from etiolated wheat seedlings (Triticum aestivum L.) and examined by native gel electrophoresis. Two of these enzymes (CAD-1 and CAD-2) were purified to apparent homogeneity. They exhibited a marked difference in substrate affinity. On sodium dodecyl sulphate-acrylamide gel the isolated isoenzymes showed only one protein band each with an M(r) 45 000 and 40 000 daltons, respectively, whereas on native gel two bands were identified for each protein. Isoenzymes from a variety of diploid, tetraploid. and hexaploid wheats were compared. The results indicated that the CAD polymorphism could be genetically determined.