[The serine proteinases of thermophilic bacilli]

The method of affinity chromatography using bacitracine as a specific ligand was applied to isolate and purify serine proteinases of 8 strains of thermophilic bacilli, including 4 strains of the species Bacillus subtilis, 2 strains of the species B. licheniformis and 2 strains of the species B. circulans. Study of physicochemical and catalytic properties of the enzymes of thermophiles has shown their complete identity with subtilysines as to molecular weight, optimal action conditions, sensitivity to inhibitors and specificity of the action both in respect to natural and in respect to artificial substrates of subtilysines. Four of eight studied enzymes (two of B. licheniformis, two of B. subtilis) were serologically relative to subtilysines of the type of Karlsberg; the rest of the enzymes did not produce the precipitation lines in the reaction of double immunodiffusion in gel with antiserum to subtilysine of the Karlsberg type. All the studied enzymes differed from commercial preparations of subtilysines (producers: B. licheniformis and B. subtilis) in the higher thermal stability: time of half-inactivation at 60 degrees C was 4.5-6 h for the enzymes from different strains of thermophiles; at 80 degrees C this value was 8-13 min. A capacity to lyse the living cells of some gram-negative bacteria and yeast is the most characteristic feature of the studied proteinases of thermophiles as against analogous enzymes of mesophilic strains of bacilli and enzymes of the animal origin.