Mating reaction inSaccharomyces cerevisiae VIII. Mating-type-specific substances responsible for sexual cell agglutination

The agglutination factors ofa and α mating types ofSaccharomyces cerevisiae were solubilized from isolated cell-wall fractions by treatment with snail enzyme (Glusulase) and shown to be adsorbed specifically by cells of the opposite mating type, resulting in the loss of agglutinability of these cells. The agglutination factors ofa and α types adsorbed by cells of the opposite mating type at pH 5.5 were eluted at pH 9.0. These factors were further purified on Sepharose 4B. From the elution pattern on Sepharose 4B, the molecular weights of the solubilized agglutination factors are estimated to be about one million. Thus purified agglutination factors contained carbohydrate and protein and were considerably resistant to heat treatment. Neutral protease ofBacillus subtilis inactivated botha and α type agglutination factors. Trypsin inactivated the α type agglutination factor only.