484 



EFFECT OF ENZYME ON DIGESTION OF PROTEINS 



If the pepsin is inactivated by boiling instead of by treatment with 

 alkali the results become irregular and do not agree with the hypoth- 

 esis that the inactivated pepsin either does or does not enter into the 

 equilibrium.^' In order to predict them quantitatively it becomes 

 necessary to assume that either the equilibrium constant is changed 



TABLE v. 

 Influence of Inactivated Pepsin on Equilibrium. 

 10 per cent Grubler's pepsin diluted as noted with, A, HCl, pH 2.0. 

 same solution inactivated by alkali. 



B, with 



or that some of the peptone also is destroyed. In any case boiling 

 causes a different change in the properties of a pepsin solution from 

 inactivation with alkali. 



Effect oj Adding Increasing Amounts of Peptone to Pepsin Solutions. 



It is possible to test further the hypothesis outlined in this paper 

 by noting the effect of adding different amounts of peptone to a con- 

 stant quantity of pepsin and comparing the observed and calculated 

 activity of the resultant solution. If, as assumed in the hypothesis, 

 the pepsin combines with the peptone to form a dissociated compound, 

 the effect of adding successive equal amounts of peptone to a constant 

 quantity of pepsin should not result in a constant decrease in activity 

 of the solution for each unit of peptone added. The first unit of 



^^An apparently similar phenomenon was noticed by Bayliss^ in his experi- 

 ments with trypsin. 



