Electroimmunochemical analysis of plasma membrane vesicles from Saccharomyces cerevisiae

Plasma membrane vesicles of Saccharomyces cerevisiae were extracted with 1% (w/v) Triton X-100 and the solubilized proteins examined by crossed immunoelectrophoresis using rabbit antibodies against the vesicles. Solubilization was shown to be nonselective and 23 immunoprecipitates were observed reproducibly. Four glycoproteins were identified by interaction with concanavalin A and lentil lectin, either immobilized on agarose beads in an intermediate gel or incorporated in the free form in the first dimension gel. One glycoprotein was stainable by the periodic acid--Schiff procedure. None of the glycoproteins had their origin in the cell wall. Five amphiphilic proteins were identified on the basis of charge-shift and hydrophobic interaction crossed immunoelectrophoresis as well as [14C]Triton X-100 and Sudan black B binding. Three of the amphiphilic proteins were also glycoproteins. Based on the carbohydrate content and amphiphilic properties of the proteins, purification schemes using concanavalin A-Sepharose and phenyl-Sepharose were proposed. Trial separations using 1-mL columns were monitored by fused rocket and crossed immunoelectrophoresis.