248 



INACTIVATION OF TRYPSIN. II 



(pepsin inactivated by heat does not act in this way). If it should be 

 found that inactive trypsin also took part in the equilibrium it is 

 evident that the experiments are complicated by an additional factor 

 that is very hard to control since there is no independent method for 

 determining the amount of inactive trypsin. In order to determine 

 this point the experiments described in Table III were performed. 

 They show that the inactive trypsin does not take part in the equilib- 

 rium. The calculated results are obtained from the law of mass 

 action as described below. 



TABLE m. 



Addition of Itmctive Trypsin. 

 2 per cent gelatin pH 6.2, specific conductivity 2 X 10~^. Trypsin, 10 per 

 cent, dialyzed, time to change 10 points = 0.10 hours = 10 units per cc. Inac- 

 tivated at 65°C. for 2 hours. Active trypsin, 10 per cent, dialyzed, diluted 

 one-third. P = 10. K' = 2.8. 



Effect of Adding Increasing Amounts of Inhibitor to a Constant 

 Quantity of Trypsin. 



The results of a series of experiments to determine the effect of 

 adding increasing concentrations of inhibitor to the same amount 

 of trypsin are given in Table IV and Fig. I. The experiments were 

 carried out by adding the noted amount of inhibiting solution to 25 cc. 

 of gelatin at 33°C. All the solutions had the same pH, which re- 



