CHARACTERIZATION OF A CELL MEMBRANE-ASSOCIATED PROTEINASE FROM LACTOBACILLUS-HELVETICUS-CRL-581

The production of a proteinase from Lactobacillus helveticus CRL 581 w as studied, The highest specific activity was found at the early expon ential growth phase of cells cultured in milk, The lowest levels of pr oteinase were detected in MRS broth, while in the casein-yeast extract -glucose broth enzyme production increased gradually during the fermen tation and reached maximal values at the stationary phase, The protein ase, found to be associated with the cell membrane fraction, hydrolyze d p-casein more rapidly than a-casein. The enzyme was not released fro m washed cells in the presence or absence of calcium, which suggests t hat the enzyme did not undergo self-digestion.