Purification and characterization of Bordetella bronchiseptica dermonecrotic toxin

Dermonecrotic toxin produced by Bordetella bronchiseptica was purified by chromatography on DEAE Toyopearl 650M and on Bio-Gel HTP, gel filtration on Sephadex G-200, and subsequent chromatography on Bio-Gel HTP and on SP Toyopearl 650M. The purified toxin was homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis and high performance liquid chromatography. There was a 90-fold increase in the dermonecrotic titer per mg protein in guinea pigs and the recovery of activity was 17.6% of that of the original cell extract. The purified toxin is a single-chain protein with a molecular weight of 145,000 and an isolelectric point of 6.3-6.7. Its minimal necrotizing dose is approximately 0.4 ng. It was completely inactivated by heating for 20 min at 56 degrees C. It contained no endotoxin, carbohydrates, nucleic acids, or hemagglutinins.