PURIFICATION AND ACTIVITY OF PROTEINASE OF STREPTOCOCCUS FAECALIS VAR. LIQUEFACIENS.

Shugart, Lee R. (University of Tennessee, Knoxville) and Raymond W. Beck. Purification and activity of proteinase of Streptococcus faecalis var. liquefaciens. J. Bacteriol. 88:586-590. 1964.-A proteolytic enzyme from Streptococcus faecalis var. liquefaciens was purified 480-fold by ammonium sulfate fractionation and treatment with calcium phosphate gel. Approximately 20% of the original enzyme activity was recovered in the purified fraction. Optimal enzyme activity was found to be at pH 7.6 and 35 C. The enzyme is apparently more susceptible to heat denaturation when complexed with substrate than when heated in the absence of substrate. Michaelis-Menten constants were found to be 0.655% for hemoglobin and 0.133% for casein. Apparent energies of activation on these substrates were calculated to be 9,060 and 12,020 cal, respectively.