JOHN H. NORTHROP 



507 



TABLE XI. 



Efect of Increasing Concentration of Casein on the Rate of Hydrolysis as Measured 

 by the Iticrease in Amino Nitrogen. 

 Casein dissolved in a mixture of m/20 Na2HP04, H3BO3, and Nas citrate of 

 pH 8.0. 100 cc. of this solution + 1 cc. dialyzed trypsin at 34°C. for time noted. 

 Amino nitrogen determined by Van Slyke method on 0.6 cc. of solution as noted. 



Increase in amino nitrogen per 0.6 cc. solution containing noted concentration of casein. 



The figures are the mean of 4 to 6 determinations. The average deviation of 

 the mean is about 5 per cent. 



TABLE XII. 



Effect of Increasing Concentration of Casein on Rate of Digestion as Measured by 

 the Decrease in Undigested Casein. 



Casein dissolved in M/20 phosphate, borate, citrate buffer pH 8.0. 100 cc. 

 solution + 1 cc. dialyzed trypsin placed at 34°C. and 10 cc. samples removed as 

 noted, titrated to pH 4.6, and added to 100 cc. 0.1 N acetate buffer pH 4.6. 

 Precipitate filtered, dried at 100°C., and weighed. 



Casein per 10 cc. solution, gm. 



Monomolecular constant for solution. 



Time to dissolve 0.02 gm. in solution, hrs. 



K = concentration casein X time to dissolve 

 0.02 gm. 



Hrs. at 34''C. 







0.15 

 0.31 

 0.50 



0.08 



0.045 



0.025 



0.0120 

 0.0140 

 0.0125 



0.25 hr. 0.50 hr. 1 hr 



0.08 



0.19 

 0.31 



1.00 

 0.90 

 0.85 



0.05 

 0.12 

 0.26 



0.96 

 0.84 

 0.60 



0.02 

 0.08 

 0.23 



0.87 

 0.60 

 0.34 



