Proteolytic Enzymes from Bacterium Linens

Abstract

An extracellular proteinase (specific activity 23.3 to 78.7 mg. of casein hydrolyzed in 1.5 hrs. per mg. of enzyme protein) was recovered from the medium after 2 days'' growth of B. linens 450, by ammonium sulfate precipitation (52 to 100% saturation). Of the proteins tested, only casein and a bovine seminal protein prepn. were attacked. The product of proteinase action is a polypeptide. No polypeptidase, and little peptidase, activity was found in the proteinase prepn. With beta-casein as the substrate, a proteolytic action superficially similar to that of rennin was observed.