The concentration of acid for which the enzymotic activity is a 

 maximum can be calculated from Equation 5. Writing its first 

 differential with respect to (H) equal to zero and solving gives 



(7) 



Substituting in this the values previously found for these constants 

 gives (fi r ) max = 0.8(10)- 3 at 30 C. Sorensen, a from his experiments 

 at 52, has found this value to be approximately (10) ~ 4 ; our results 

 are thus in fair agreement with his, but they can not be strictly 



0.01 



0.01 



0.02 



0.03 



0.04 



0.05 



FIG. 1. Graph of the formula for the activity of invertase. 



compared because of the different temperatures used, namely, 52 

 and 32 C. 



From the value of K it is seen that invertase is a very weak acid, 

 far weaker than acetic; from the value of K 2 /K W it is seen that inver- 

 tase is a much weaker base, being only 133 times as strong as water 

 itself. 



aComptes rendus des travaux du Laboratoire de Carlsberg, 1909, 8 : 132. 

 [Cir. 60] 







