Central carbon metabolism of Plasmodium parasites.
Rhesus monkey erythrocytes infected with P. knowlesi at high degrees of synchrony were metabolically labeled in vitro during the early schizont stage, using 14C-amino acids and 14C-glucosamine as precursors. Parasite-specific proteins in purified schizonts and host-cell membranes were characterized by their isoelectric points and molecular masses, using isoelectric focusing in polyacrylamide and dodecyl sulfate polyacrylamide gel electrophoresis, respectively. Both 14C-amino acids and 14C-glucosamine caused labelling of 60,000-90,000D proteins/glycoproteins, focusing between pH 4.5 and pH 5.2. The plasmodial parasites synthesized gangliosides and/or other glycolipids, leading to their appearance in the host cell membrane.