9 8 



Scientific Proceedings (38). 



week to week until finally the enzyme solution is more active in 

 alkaline than in acid medium. For instance, 2.5 grams of fresh 

 liver after five days autolysis yields an equivalent in 0.2 per cent, 

 acetic acid, of 29.4 cubic centimeters N/10 H 2 S0 4 ; in neutral of 

 7.9 cubic centimeters N/10 H 2 S0 4 ; and in 0.2 per cent, sodium 

 carbonate, of 2.0 cubic centimeters N/ 10 H 2 S0 4 ; whereas after 

 standing fifty-five days on the ice the same liver gives in 0.2 per 

 cent, acetic acid 17.6 cubic centimeters N/10 H 2 S0 4 ; in neutral 



21.7 cubic centimeters N/10 H 2 S0 4 , and in 0.2 per cent, sodium 

 carbonate 24.2 cubic centimeters N/10 H 2 S0 4 . This rise of auto- 

 lytic activity in neutral and alkaline media is analogous to the 

 rise of tryptic activity of pancreatic extracts on standing, and is 

 probably attributable to the slow conversion of an alkaline digest- 

 ing enzyme from an inactive into an active form. 



Activation of the alkaline enzyme can be accomplished more 

 rapidly by pretreatment of fresh liver with weak acetic acid, a 

 method first used by Hedin in demonstrating the alkaline enzyme 

 of spleen. Two and a half grams of fresh untreated liver after 

 five days autolysis at 37° C. yields an equivalent in 0.2 per cent, 

 acetic acid, of 34.8 cubic centimeters N/10 H 2 S0 4 ; in neutral, of 



12.8 cubic centimeters N/10 H 2 S0 4 ; and in 0.2 per cent, sodium 

 carbonate, of 7.7 cubic centimeters N/10 H 2 S0 4 . The same liver, 

 treated with 0.4 per cent, acetic acid for twenty-four hours on ice, 

 gives after neutralization of the acid, equivalents in 0.2 per cent, 

 acetic acid, of 22.5 cubic centimeters N/10 H 2 S0 4 ; in neutral, of 

 17.2 cubic centimeters N/10 H 2 S0 4 ; and in 0.2 per cent, sodium 

 carbonate, of 16.8 cubic centimeters N/10 H 2 S0 4 . Previous 

 treatment of fresh liver with alkali results in the destruction of 

 practically all proteolytic activity. Two and a half grams of liver, 

 treated for twenty-four hours on ice with 0.4 per cent, sodium 

 hydrate, yield, after neutralization, an equivalent in 0.2 per cent, 

 acetic acid, of 3.9 cubic centimeters N/10 H 2 S0 4 ; in neutral, of 

 0.4 cubic centimeter N/10 H 2 S0 4 ; and in 0.2 per cent, sodium 

 carbonate, of o. 1 cubic centimeter N/10 H 2 S0 4 . There is some 

 reason to believe that the inactivity following pretreatment of liver 

 with 0.4 per cent, sodium hydrate does not represent destruction 

 of the proteolytic enzymes, but is due to the fixing of the enzyme 

 in the inactive state in which it exists in the cells. When fresh 



