Mating reaction in Saccharomyces cerevisiae. X. Agglutinability-inactivating factor: a factor which destroys sexual agglutinability of a mating-type cells.

From cells of Saccharomyces cerevisiae a factor has been extracted that destroys the agglutinability of a mating-type cells specifically. It was found in the cell extracts of diploid and tetraploid strains as well as haploid strains of a and alpha mating types. It is heat-labile and the molecular weight is about 50,000. It is adsorbed by neither a cells nor alpha cells. Its biological activity is dependent on the incubation temperature and the pH, and is completely inhibited by phenylmethylsulfonyl fluoride, a potent inhibitor of the serine proteases. All the results described in this paper indicate that this factor is a proteolytic enzyme.