PROPERTIES OF A LYSOZYME-DISSOCIATED ENDOTOXIC FRACTION FROM ESCHERICHIA COLI

Abstract

Treatment of a phenol-water preparation of C14-labeled E. coli O91-H21 endotoxin of low solubility with lysozyme at pH 5.0 or 8.0 effected a dissociation of the preparation. Such products of dissociation were equally distributed in the chloroform and water phases after extraction. [beta]-Gluco-sidase, but not [beta]-galactosidase, significantly dissociated this endotoxin also. Concomitant with dissociation, recoverable endotoxin after lysozyme treatment had a reduced content of bound lipid, and dissolved easily in aqueous media to yield a clear solutioa Examination of lysozyme-treated endotoxin in an analytical ultracentrifuge revealed that it sedimented as a single major boundary with a sedimentation coefficient of 13.3. Lysozyme-treated endotoxin was more potent than was the conventional endotoxin as evidenced by lethal activity in rabbits and pertussis-sensitized mice. Agar-gel diffusion analysis indicated that the higher molecular weight component associated with conventional endotoxin was dissociated by lysozyme treatment. In immunoelectrophoresis, lysozyme-treated endotoxin was observed as a single sharp band of precipitation which migrated toward the cathode.