THE KINETICS OF TRYPSIN DIGESTION : IV. THE COURSE OF THE REACTION WHEN BOTH SUBSTRATE AND ENZYME CONCENTRATIONS ARE DECREASING.

The rate of hydrolysis of edestin by trypsin at 40° and in the presence of 1 M NaCl has been studied. Under these conditions the enzyme is rapidly inactivated and the equation for the reaction may be written See PDF for Equation in which E(t) is the concentration of enzyme during the interval (T (1)–T (2)). This equation has been tested by determining the enzyme concentration at various times during the reaction and substituting these values in the above equation. The experimental results agree with this formula when the initial enzyme or edestin concentrations are varied. No anomalous results of varying substrate concentrations are apparent. It can further be assumed as a first approximation that the enzyme is decomposing monomolecularly and the equation can then be written See PDF for Equation This equation is also satisfactory provided high enzyme concentrations and low edestin concentrations are used. With high concentrations of edestin and low trypsin the effects of the products of the reaction on the enzyme become too large to be neglected and the formula no longer holds.