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exotoxin
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exotoxin

biochemistry
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History

exotoxin, a poisonous substance secreted by certain bacteria. In their purest form they are the most potent poisons known and are the active agents in diphtheria, tetanus, and botulism. The term is now sometimes restricted to poisonous proteins that are antigenicā€”i.e., that stimulate the formation of antibodiesā€”and formed by gram-positive bacteria. Compare endotoxin.