Studies on polyphenol oxidase in wheat grains

Abstract

Polyphenol oxidase was partially purified from the bran fraction of mature grains of tall and dwarf varieties of wheat. The specific activity of the enzyme in dwarfs is distinctly higher than in tall varieties. Furthur, the enzyme in dwarfs is relatively more thermostable. Substrate specificity studies showed that diphenols are efficient substrates, whereas mono- and polyphenols are poor substrates. Fractionation of isoenzymes of polyphenol oxidase on acrylamide gel electrophoresis revealed three to five bands. Usually the isoenzymes of dwarf varieties are more stable on storage at 4° C. than their counterparts in the tall varieties.