Studies on Enzyme Action. 



377 



with any of the salts. They came to the conclusion that the higher the 

 molecular weight of the acid, the more readily is its ethylic salt hydrolysed 

 by lipase. 



Eicinus lipase, at least in the form in which we have used it, has a very 

 slight action on ethylic acetate, but gradually hydrolyses the butyrate. 

 Alone it produces little or no effect, mixtures of 2 grammes of seed residue, 

 3 c.c. ethylic butyrate and 200 c.c. water requiring for neutralisation at the 

 end of 21 hours only 0*7 c.c, after 45 hours 1 c.c. and after 117 hours 

 1*75 c.c. of normal alkali. 



In presence of dilute N/5 acetic acid, action takes place slowly, as shown 

 in the following table — in which the values represent the number of cubic 

 centimetres of normal alkali neutralised : — 



21 hours 

 45 „ 

 69 „ 

 112 „ 



2 grs. seed residue. 

 20 c.c. acetic acid. 

 200 c.c. water. 



018 

 0--20 

 0-20 

 0-20 



B. 



3 c.c. ethylic butyrate. 

 20 c.c. acetic acid. 

 200 c.c. water. 



0-2 

 0-2 

 0-2 

 0-25 



C. 



2 grs. seed residue. 

 20 c.c. acetic acid. 



200 c.c. water. 



3 c.c. ethylic butyrate. 



7-02 

 1010 



The extent to which hydrolysis is effected depends both on the amount of 

 enzyme and, up to a certain point, on the proportion of acid present; 

 thus the following results were obtained, using x grammes of seed residue, 

 0'4 c.c. toluene, T5 c.c. ethylic butyrate, y c.c. N/5 acetic acid, water to 

 100 c.c/ 



Seed residue. 



Cubic 

 centimetres of 



Cubic centimetres of alkali required by acid 

 liberated after — 



acetic acid. 



19 hours. 



43 hours. 



67 hours. 



gramme. 











1 



2 



3 5 



8-5 



13 -0 



1 



5 



6-5 



11 -5 



16 -0 



1 



10 



7-0 



13 -0 



16 -5 



1 



20 



9-6 



19 -5 





0-5 



3 



3-0 



5 



7-5 



The extent to which the activity of the enzyme is influenced by acids is 

 illustrated in the following table, in which the values represent the number 

 of cubic centimetres of a normal solution of caustic soda required to 

 neutralise the acid liberated in a series of comparable experiments, in each 



