Purification and characterization of cytotoxin from the crude extract of Pseudomonas aeruginosa

Pseudomonas aeruginosa cytotoxin is a protein toxin exhibiting cytotoxic effects on various eukaryotic cells. The toxin was purified from a crude extract of Pseudomonas aeruginosa 158 by trypsin treatment and serial chromatography. The purified cytotoxin was electrophoresed as a single protein band on polyacrylamide gel electrophoresis (PAGE) in the presence or absence of sodium dodecyl sulfate (SDS). The molecular weight of the purified toxin was determined to be 29000 by SDS-PAGE and gel filtration chromatography in the presence of 6 m guanidine hydrochloride; the isoelectoric point was pH 6.0. The N-terminal amino acid sequence of the purified toxin was determined. The purified toxin showed the strongest cytotoxic effect on rabbit polymorphonuclear leukocytes and diverse degrees of cytotoxic effects on various eukaryotic cells including red blood cells and cultured cells.