178 Prof. H. E. Armstrong and Mr. H. W. Gosney. 



To discover whether a true equilibrium had been reached or whether the 

 action had ceased owing to the destruction of the enzyme, 0'5 grm. ot 

 enzyme was added to the system after the expiration of 24 hours and the 

 mixture was titrated at the end of a second period of 24 hours. Experiments 

 were also made in which - 5 and 1 grm. of the enzyme were allowed to act 

 during 48 hours before titrating the residual acid. 





Percentage of acid 

 combined 



"5 grm. enzyme during 24 hours 



0- 5 48 



1- 48 



0-5 24 



Together with - 5 grm. during a second 

 period of 24 hours 



37 -4 

 37 -7 

 33 6 



J" 34 -9 

 \35-3 



The slightly lower activity observed in the experiments with 1 grm. of 

 enzyme may have been due to the slight amount of water introduced with 

 the preparation. 



Further evidence that a true equilibrium had been reached was obtained 

 on hydrolysing olive oil by the theoretical minimum amount of water, 

 i.e. three molecular proportions to each molecular proportion of triglyceride 

 or 5 grm. of oil and 0*53 grm. of water, quantities equivalent to those used 

 in the synthetic experiments. As in the reverse case, the equilibrium was 

 quickly reached and the acidity of the system was approximately the same 

 as that observed in the experiments in the reverse direction. 



Table II. — Hydrolysis of Fat by three Molecular Proportions of Water. 



Time 



Percentage of acid liberated 



hours 





1 



30 -6 



2 



45 -5 



4 



56 -0 



8 



61 -3 



17 



62 -0 



30 



62 9 



50 



62 -6 



68 



62 -0 



The addition of even a small amount of water influences the equilibrium 

 to a marked extent and also has a retarding effect — to an increasing extent, 

 moreover, as the amount of water is increased. This is shown in the 

 following table, in which are recorded the results obtained by the synthetic 

 action of 0-5 grm. of enzyme on mixtures of 4 - 84 grm. of fatty acid from 



