Characterization of glycopeptides from physarum polycephalum labeled with [³H]mannose or [³H]glucosamine

Glycopeptides from the microplasmodia of Physarum polycephalum grown in the presence of [³H]mannose or [³H]glucosamine were characterized by gel-filtration, anion-exchange and lectin-affinity chromatography before and after enzymatic or chemical treatment. Various types of glycopeptide were found in the growing plasmodia as shown by Con A affinity column chromatography, while pulse-labeled precursors were composed mainly of mannose-rich glycopeptides which were sensitive to endo H and a-mannosidase. During the processing of the glycoprotein, the mannose-rich glycopeptides changed to larger glycopeptides which were resistant to endo H and a-mannosidase. These processing reactions of the glycoprotein appeared to be blocked when the plasmodia underwent differentiation to macrocysts.