Ccxx. Enzymic Adaptation in Clostridium Histolyticum

RECENTLY Kocholaty & Hoogerheide [1938] described an example of the adaptation of certain of the endo-enzymes of the strict anaerobe Cl. sporogenes: by varying thepH ofthe culture medium a considerable shift in the pH optimum of some of the dehydrogenases could be produced. It has now been found that under specified conditions the pH optimum of the proteinase secreted by this micro-organism can be shifted, and that, by repeated subculturings on gelatin or casein, specific proteinases are developed which will hydrolyse gelatin, but not casein, and vice versa. EXPERIMENTAL The methods used in preparing the Cl. histolyticum proteinase and estimating its activity were the same as previously described [Kocholaty et al. 1938]. Casein (Hammarsten) and gelatin (Coignet Gold Label) were used as culture media, and as substrates for proteinase activity determinations. Bacteria-free Seitz ifitrates of the incubated cultures were used in the enzyme studies.