Characteristics of an Endocellular Proteolytic Enzyme System of Streptococcus Lactis

Abstract
Cell-free extracts prepared by sonic vibration of cells of S. lactis were tested for proteolytic activity against milk, casein, and lactalbumin. Opt. activity was at pH values near neutrality. The presence in the growth medium of nicotinic acid and casein increased the proteolytic activity of the cell-free extract. Some of the characteristics of this proteolytic enzyme system were studied.