INFLUENCE OF ADDED SUBSTANCES 



415 



TABLE III 



Ten grams of protamin sulphate in 1 litre of solution. Ten milligrams 

 of trypsin and 2.1 cc. of AT/10 NaOH to 25 cc. 



5. The Influence of Added Substances upon the Rate of 

 Protein Hydrolysis by Enzymes. The influence of added 

 substances upon the rapidity of the hydrolysis of proteins by 

 enzymes has been extensively studied, owing to its supposed 

 importance in connection with the digestion of protein in the 

 alimentary canal (97) (119) (51) (149) (73) (16) (96) (45) (18) 

 (151) (30) (66) (15) (100) (152) (120). Despite this extended 

 investigation, however, the results obtained by different observers 

 have been conflicting in the extreme. Investigations which I 

 have carried out on the influence of salts upon the hydrolysis 

 of caseinates by trypsin indicate the probable source of the dis- 

 crepancies between the results of different observers (107). I 

 find that the order of efficiency of salts in accelerating the hy- 

 drolysis of casein by trypsin is the order of their efficiency in 

 accelerating the solution of casein by alkalies. If this rule holds 

 good for other proteins, then one might anticipate that the 

 influence of salts upon their hydrolysis by enzymes would vary 



