1913.] 



Studies on Enzyme Action. 



591 



These results show that the recovery of activity, even in presence of a 

 considerable excess of the " basic " material, is only moderate ; they appear 

 to justify Tanaka's conclusion that the enzyme is more active under neutral 

 than under acid conditions. 



The inferiority of the tartaric product is equally obvious when tested by 

 . means of oil. Thus on digesting 0-5 grm. of the powder with 5 grm. of olive oil 

 and 2 c.c. of water during 20 hours, the amounts hydrolysed were as follows : — ■ 



Enzyme a prepared with Enzyme prepared with 

 acetic acid tartaric acid 



(1) 7 7 "6 per cent. 45 - 1 per cent. 



(2) 75-5 ,. 48-4 „ 



To test the effect of concentration, three 5 grm. samples of oil-free meal 

 were digested with equal volumes (40 c.c.) of solutions of tartaric acid of 

 different strength (N/5, N/10, N/40) and after washing and drying, - 5 grm. 

 of each product was digested with 10 c.c. of a solution of succinic ether. 

 The amount of hydrolysis effected in 20 hours was : — 



Untreated enzyme 51 '1 per cent. 



Digested with N/5 acid 30'9 „ 



N/10 „• 41-5 



N/40 „ 8-5 



As it was possible that insufficient acid had been used in the case of the 

 N/40 solution, a constant amount of tartaric acid but different volumes of 

 the solution were used. 



Enzyme prepared with the aid of 20 c.c. N/5 acid hydrolysed 42 - 6 per cent. 



40 „ N/10 „ 43-9 „ 



80 „ N/20 „ 54-4 „ 



160 „ N/40 „ 461 „ 



The following two tables afford further illustrations of the influence of 

 acids : — 



Table showing the Effect of increasing Amounts of various Acids on 0'5 grm. 

 of treated Enzyme acting during 20 hours on 10 c.c. M/20 Solution of 

 Succinic Ether. 



Concentration 

 of acid 



Glycine 



B utyric 



Succinic 



Malic 



Tartaric 



Sulphuric 



No acid 



58 -5 



56 5 



60 -3 



58 -7 



60 -7 



55 '7 



N/40 



57 -6 



60 5 



56 -7 



60 3 



58 -8 



8-1 



N/20 



61 -3 



61 -8 



55 -8 





52 -6 





N/10 



63 -5 



57 '3 



55 -0 



56 -6 



33 3 





N/5 



70 -2 



44 -2 



55 -6 



51 -1 



5-2 





N/3-3 





17 -0 



53 -6 



21 -2 







VOL. LXXXVI. — B. 2 X 



