STUDIES ON DEBRANCHING ENZYMES. PART I THE LIMIT DEXTRINASE ACTIVITY OF EXTRACTS OF CERTAIN HIGHER PLANTS AND COMMERCIAL MALTS

Using pullulan as the substrate, the limit dextrinase activity of protein extracts from higher plants and from commercial malts has been measured. Extracts of ungerminated barley, rye, maize and wheat show low levels of activity which increase markedly on germination. By contrast, extracts of ungerminated oats have a high level of activity which does not increase during germination. Gibberellic acid has a significant effect on the rate of development of limit dextrinase activity in barley. Commercial samples of malt show varying amounts of limit dextrinase activity which does not correlate with the diastatic power. For comparative purposes, the α-amylase and maltotriase activities of all the protein extracts have also been measured.