ACTIVITY OF TYPE A BOTULINAL TOXIN AND HEMAGGLUTININ EXPOSED TO PROTEOLYTIC ENZYME

Abstract

Type A botulinal toxin is not inactivated by the proteolytic enzymes of animal, plant, and bacterial origin. Toxicity is lost by exposure to trypsin, chymotrypsin, ficin, type B botulinal aminopeptidase, and glutamyl transferase of Bacillus subtilis. Pepsin and papain appear not to affect toxicity appreciably. The effect of the enzymes is independent of the relative content of toxin to hemagglutinin. Relative to casein the enzymes act more slowly when the toxin is the substrate. Possibly the toxin acts as an oral poison in spite of its lack of absolute resistance to intestinal proteolysis because of its slow digestion and persistence in the alimentary tract. At pH 4.38 the diffusion coefficient of the toxin was shown to become greater when the ratio of toxicity to hemagglutination was increased by removal of hemagglutinin.