title: Yeast killer toxin: purification and characterisation of the protein toxin from Saccharomyces cerevisiae.
abstract: Killer toxin from killer strains of Saccharomyces cerevisiae was isolated from concentrates of extracellular medium by precipitation in poly(ethylene glycol) and chromatography through glyceryl-controlled-pore glass. The toxin migrated as a single protein band on sodium dodecyl sulfate/polyacrylamide gel electrophoresis. A molecular weight of 11470 was determined for the toxin protein from its electrophoretic mobility and amino acid composition. Gel filtration of the active toxin indicated that the 11,470-Mr monomer was the active unit. Electrophoretic comparison of extracellular concentrates from a killer strain and an isogenic non-killer showed the presence of the toxin protein only in the killer-derived material. The activity of the toxin was most stable between pH 4.2 and 4.6. At 30 degrees C toxin from a superkiller strain was more stable than that from a normal killer.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D005656:Fungal Proteins / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009183:Mycotoxins / Q000032:analysis / Q000302:isolation & purification*; D012441:Saccharomyces cerevisiae / Q000187:drug effects
chemical_list: D000596:Amino Acids; D005656:Fungal Proteins; D009183:Mycotoxins