Barley powdery mildew "Invertase" is an alpha-glucosidase

Abstract

Extracts from barley powdery mildew (Erysiphe graminis hordeii) were found to contain sucrose-hydrolase and α-glucosidase activities with identical pH optima. When fractionated by anion-exchange and size exclusion chromatography, these extracts showed coincidence of the two enzyme activities in the fractions obtained. Experiments were performed in which sucrose was hydrolysed in the presence of H218O by yeast invertase (E.C. 3.2.1.26), yeast α-glucosidase (E.C. 3.2.1.20), and by an extract from the mycelium of barley powdery mildew. Using GC/MS, the distribution of18O between derivatives of the hexose products of each reaction was determined. From a comparison of the results, it is concluded that the hydrolysis of sucrose by the powdery mildew extract was catalysed by an α-glucosidase. © 1988 Springer-Verlag.