Abstract
It is shown that various microbial and animal proteinases, with the exception of pepsin, have a lytic effect on peptide- and protein-lignosulphonic acid complexes in agar gel, and that this effect is characteristically inhibited by specific antiproteinases and naturally occurring serum inhibitors. The activity of the enzymes is studied at various concentrations of peptides and proteins, and at various pH values in the agar. The lysis phenomenon is seen in relation to the precipitation theory of peptide- and protein-lignosulphonic acid complexes, and to biochemical reactions taking place in certain natural ecosystems. Activity caused by different microbial proteinases is demonstrated in agar plates at pH 3.6. The possibility of using the method for studies on proteolytic enzymes at low pH values is suggested.