This substrate is used to deternimate the milk clotting activity of proteases.
2.
However, milk clotting may take place without the participation of enzymes because of variations in physicochemical factors, such as low pH or high temperature.
3.
Enzyme activity can also be given as that of certain standardized substrates, such as gelatin, then measured in " gelatin digesting units " ( GDU ), or milk proteins, then measured in " milk clotting units " ( MCU ).