EFFECTS OF PATHOGEN-RELATED PROTEINS FROM BARLEY-GRAIN ON BREWERS-YEAST

Two basic glycoproteins homologous with thaumatin- and pathogen-relate d proteins of the PR-5 family were isolated from grain of brewers barl ey cultivar. The proteins inhibit fermentation and respiration of brew ers yeast and exert a lethal effect on the yeast cells. In addition a significant release of cell constituents was registered. All these eff ects are dose dependent and tend to saturation at higher dosage. These results suggest that cell membrane damage causes the impairment of vi tal cell functions. Tracing these proteins in the course of the brewin g process revealed that thermal treatment at the mashing stage of brew ing leads to their disappearance due to denaturation.