Significance of 12 S Toxin of Clostridium botulinum Type E

Abstract

The pathogenesis of type E botulism is discussed as an aspect of the physicochemical and biological properties of 12 S toxins (prototoxin and trypsin-activated 12 S toxin) and the Eα and Eβ components of each 12 S toxin. A molecular weight of 350,000 was determined for each 12 S toxin and 150,000 for Eα and Eβ. Owing to the structure comprising the subunits Eα and Eβ, 12 S toxins are much more stable than Eα at low p H values and high temperatures. Such was also the case with type A 19 S toxin and its α component. The Eα component alone accounts for the total toxicity of type E toxin. The toxic substance detected in the blood of the animals administered 12 S toxins orally or parenterally was identified as Eα from the molecular size and the chromatographic pattern. Prototoxin escaping from detoxification in the stomach owing to the subunit structure may undergo dissociation in the intestine to release the Eα component. After absorption, the activated Eα appeared in the circulating blood without any further signs of dissociation or enzymatic digestion.