Glycoproteins and enzymes associated with the plasmodial membrane and slime layer of physarum polycephalum

Proteins and slime substances were extracted from the membrane fraction of the actively growing plasmodia of Physarum polycephalum, and analyzed by SDS-PAGE. A glycoprotein with a molecular weight of 120kD had a very high affinity for concanavalin A. The synthesis of this glycoprotein was greatly inhibited by tunicamycin. When the culture entered the stationary phase, the plasmodia produced large amounts of the slime on their surface. In the shaken culture, most of the slime substances were released from the plasmodial surface together with the 120kD glyco-proteins. In this growth phase, some gelatinolytic glycosidase and hemagglutinating activities were also released into the medium. Some of these had appeared in the membrane fraction of growing plasmodia. The results suggest that these biologically active molecules are associated with the plasmodial membrane together with slime substances.