Increased extracellular secretion in fragile mutants of Saccharomyces cerevisiae.

Evidences are presented for a generally increased extracellular secretion capability of the fragile mutants of S. cerevisiae. Proteins secreted in wild type yeasts to the periplasmic space can not be retained by the defective cell wall of the fragile cells and are released into the medium. Changes in the structure of non-mannan components of the cell wall might be the reason for the extracellular release of the periplasmic proteins.