The bacillus cereus toxin: isolation of permeability factor.

The Bacillus cereus protein has been obtained from culture fluid in homogenic form as indicated by SDS-disc electrophoresis and immunodiffusion not described before. The protein has a molecular weight of 100000 daltons. Purification was accomplished by the following steps: (1) removal of ballast nitrous components with DE-32 cellulose at pH 7.2; (2) removal of the proteins from the culture filtrate (deluted four times by water) with DE-32 cellulose at pH 8.6; (3) elution by 0.005 M tris-HCl buffer at pH 7.0 containing 0.5 M NaCl; (4) column rechromatography on DE-32 cellulose at pH 8.6. The isolated protein was identified as a vascular permeability factor acording to the bluing zone in rabbit skin tests or to the bluing lung tissue in mice.