CHARACTERIZATION OF ANTHRAX TOXIN
ARMY MEDICAL UNIT FREDERICK MD
Pagination or Media Count:
An efficient preparative column chromatography procedure was developed which was adaptable to ultrafiltrate residue, crude filtrates, or batch collection. Yields of 80-85 of the initial biological activity were obtained in the fractions studied. The protective antigen-II and lethal factor- III fractions prepared by this method appeared to be pure by immunochemical analysis and disc electrophoresis, but they must be subjected to further analyses in order to meet the standard criteria of purity. The EF-I has been recorded only qualitatively in this presentation. A similar quantitative analysis for this substance by chromatography requires a more precise bioassay procedure. Free chromophore groups, seen in the dialysis filtrate, may be synthesized in excess of the protein moiety of the chromogen component. Since the chromagen and its chromophore are actively aggregating substances, they may act as absorption centers for other proteins and this capability may account for chromagen contamination in chromatographic fractions. The influence of chromagen upon the physiochemical behavior of those proteins is not known. The presence of considerable amounts of a basic polypeptide in these culture filtrates might contribute to aggregation with the more acidic chromagen or LF- III protein. While this aggregation might contribute to that observed in ultracentrifugal fractions 2, it apparently does not exert a significant effect upon column fractions from DEAE-cellulose. The basic protein is readily dissociated from acidic proteins by the ion-exchange procedure. In none of the preparations studied has there been evidence to indicate that the components responsible for lethality in the rat exist as a single chemical entity.