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 gas tric mucin. The lectin was characterized with respect to molecular arc hitecture, carbohydrate specificity, and amino acid and carbohydrate c omposition. Among the various enzyme activities which also occur in th e mushroom, we found that a phosphatase interacts with the lectin. The phosphatase was partially purified. The interaction significantly enh ances the activity of the enzyme. The kinetic parameter which increase s is the maximal velocity (V-max), whereas the Michaelis-Menten consta nt (K-m) remains virtually unchanged. The interaction and hence activa tion can be prevented by preincubation with galactose but not glucose. This indicates that both proteins interact by the carbohydrate bindin g site of the lectin.