Activity of Type a Botulinal Toxin and Hemagglutinin Exposed to Proteolytic Enzyme

Correlation between oral toxicity and in vitro stability of Clostridium botulinum type A and B toxins of different molecular sizes

“…It appeared also that the larger the molecular size of the toxin of a given type, the higher the resistance to pepsin and gastric juice. Type A crystalline toxin was previously shown to be resistant to pepsin (3,8). It seems that this resistance is dependent not only on the molecular size but also on some other factors, since type B-L toxin was more resistant than A-L toxin (the former consisted of the 16S molecules only, whereas the latter was a mixture of 16S and 19S molecules).…”

“…By both pancreatic digestion at pH 6.5 and exposure to intestinal juice of pH 7.0, the derivative toxin was found to be partially or completely inactivated; the progenitor toxin resisted both treatments. It has been reported that type A crystalline toxin is susceptible to trypsin and chymotrypsin (1,3,8); prolonged incubation with a larger amount of these enzymes would inactivate more progenitor toxins. The results indicate that the derivative toxin, if not inactivated in the stomach, would be destroyed by the proteolytic enzymes in the small intestine.…”

“…It has been reported that type A crystalline toxin is resistant to pepsin and papain but susceptible to trypsin, chymotrypsin, and some other proteolytic enzymes (1,3,8). It has also been reported that type A crystalline and type E and F progenitor toxins are significantly more stable than the corresponding derivative toxins, particularly at low pH values (5, 9).…”

Botulinal toxins and the problem of nomenclature of simple toxins.

“…The botulinal toxins reveal still another kind of structure, namely the coexistence of different simple protein entities within a complex, only one of which is toxic, and held together by bonds easily broken by physical forces. Chromatographic separation (14, 17) and selective adsorption and elution from red-blood corpuscles (34) succeed in increasing the toxic potency of purified and crystalline botulinal toxins by separation of a nontoxic entity. This result is inconsistent with the thought that one is dealing with a polymer.…”

Influence of Ingested Foods on the Oral Toxicity in Mice of Crystalline Botulinal Type a Toxin

“…Autopsy of more than 80 mice revealed no evidence of perforation or signs of local hemorrhage along the route of injection. Lamanna, 1959). Evidently the capacity to act as an oral poison cannot be a matter of absolute I This investigation was sponsored by the Office of Naval Research and the Bureau of Medicine and Surgery, U. S. Navy, under a contract between the Office of Naval Research and the Regents of the University of California.…”