The Relation of Toxicity and Enzyme Activity in the Lecithinases of Clostridium bifermentans and Clostridium welchii

Abstract

Methods of preparing and estimating lecithinase for hemoglobin and toxicity tests are described. Curves for the amt. of acid-soluble P liberated from egg yolk extract, whether plotted against time or against concn. of dose after a fixed time, are similar in shape. Statistical analysis of regressions of log dose against acid-soluble P in terms of slope and of dose required to liberate 50 ug. of P (O.L.50 P) showed marked differences between C. welchii lecithinase (W.L.) and C. bifermentans lecithinase (B.L.), with lesser differences due to the different strains. (Strains of bifermentans showed 9, 60 and 75 times less activity than corresponding amts. of welchii lecithinase). Chromatographic analysis of the breakdown products provided evidence that the acid soluble P compound is phosphylcholine. Toxicity to mice and hemolytic activity varied considerably in different strains. B. L. is neutralized by W.L. alpha-antitoxin but this is less than 1/500 as effective as against alpha-toxin. B.L. is highly active in an 18-hr. yolk extract and is more stable. Antigenic evidence is not against the alpha-toxin of C. welchii being identical with the lecithinase.