THE LECTIN FROM PLEUROTUS-OSTREATUS - PURIFICATION, CHARACTERIZATION AND INTERACTION WITH A PHOSPHATASE

From the fruiting bodies of the edible mushroom Pleurotus ostreatus, a lectin was isolated by affinity chromatography on immobilized hog gastric mucin. The lectin was characterized with respect to molecular architecture, carbohydrate specificity, and amino acid and carbohydrate composition. Among the various enzyme activities which also occur in the mushroom, we found that a phosphatase interacts with the lectin. The phosphatase was partially purified. The interaction significantly enhances the activity of the enzyme. The kinetic parameter which increases is the maximal velocity (V-max), whereas the Michaelis-Menten constant (K-m) remains virtually unchanged. The interaction and hence activation can be prevented by preincubation with galactose but not glucose. This indicates that both proteins interact by the carbohydrate binding site of the lectin.