values ; in order to determine the values of these coefficients the data 

 which were found for the activity of invertase in three solutions con- 

 taining small concentrations of hydrochloric acid are used, namely : a 



HCl concen- 

 tration. 

 Normal. 



Activity of 

 invertase. 



0. 0005 62 



.0015 61 



.008 37 



These data when introduced in equation (5) give the values a = 77, 

 Ay/L w =133, and #i =0.000086, and Formula 5 becomes 



Activity 



77 



0.000086 

 (H) 



(6) 



From this formula the activities of invertase over a considerable 

 range of acidity and alkalinity have been calculated and are recorded 

 in Table 1 in comparison with the activities which were found experi- 

 mentally. 



TABLE 1. Calculated and observed activities of invertase. 



By reference to the figure it will be seen that there is a remarkably 

 close agreement between the calculated and observed activities. On 

 account of the rapid destruction of invertase at 30 C. by acid above 

 .01 normal the relation can not well be tested beyond that concen- 

 tration, but it is probable that at such measurements can be made, 

 .and this will be .attempted in the near future. 



The value of the quantity a, namely, 77, indicates that at no con- 

 centration of acid is all the invertase active, and at the point of 

 maximum activity the proportion of invertase which is active is 

 63/77, or 82 per cent of all the invertase present. 



U. S. Dept. Agr., Bureau of Chemistry Cir. 55, p. 4. 



{Cir. 60] 



