The partial purification, separation, and properties of yeast killer toxins.

Two different kinds of yeast killer toxins (YKT) have been partially concentrated and their properties and molecular behaviour comparatively studied. The toxin of the first system (YKT1) shows more sensitivity to several agents (temperature, pH, enzymes) than the toxin of the second system (YKT2). YKT1 shows only one chromatographic band on Sephadex G-200, while YKT2 shows two bands. The molecular weights of these bands have been estimated. Both toxins can be separated by isoelectrofocusing and show estimated isoelectrical points of 5.4 (YKT1) and 4.3 (YKT2).