The Extracellular Proteolytic System of Clostridium parabotulinum

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Abstract
The relation of the extracellular proteolytic system to toxin production was studied. A "proteinase" which acts on gelatin and casein, optimum at pH 7, is secreted into the medium. It is inactivated by NaCN, cysteine, H2O2 and copper salts. The lower members in the proteolytic system included a polypeptidase acting on Witte''s peptone, an aminopolypeptidase, hydrolyzing leucyl-glycyl glycine and a dipeptidase, hydrolyzing leucyl glycine. The optimal pH values for these enzymes were 7.8-8. The proteinase appeared first in the culture fluid, at least 6 hrs. before the toxin could be demonstrated; its amt. paralleled the trend of bacterial N. The polypepti-dases and dipeptidase appeared simultaneously with toxin but whereas the toxin reached its maximum around the 96th hr., these enzymes increased slowly during the first 6 days. When during the normal growth of the organisms the proteinase was inactivated by the presence of NaCN in the medium, the production of toxin was unchanged and unaltered. Various types of Cl. botulinum showed no correlation between the extracellular proteolytic enzymes and toxin production. Types "C" and "D" produced large amts. of toxin, comparable with the proteolytic Type "A" in the absence of any detectable quantities of proteinase. Strains of Type "B" produced amts. of proteinase comparable to that of Type "A" but produced ca. 1/10 as much toxin.

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