1906.] 



Studies on Enzyme Action. 



381 



0"3 gramme of seed residue. 



1 c.c. ethereal salt. 



01 c.c. of toluene. 



5 c.c. of N/5 acetic acid. 



Water to 50 c.c. 



Cubic centimetres N/5 NaOH required to neutralise Acid liberated by 



Lipase after — 



29 hrs. 6 days. 



Ethylic malonate 5"5 1035 



„ succinate 1T75 3075 



„ malate 3 - 5 13 - 5 



„ tartrate - 5 05 



The formulae of the four salts are as follows : — 



/COOEt CH 2 .COOEt CH 2 .COOEt CH(OH).COOEt 

 CH 2 < i i i 



x COOEt CH 2 .COOEt CH(OH).COOEt CH(OH).COOEt 



Et. malonate Et. succinate Et. malate Et. tartrate 



In view of the position which it occupies between the succinate and 



tartrate and of its relation to ethylic malonate, the behaviour of ethylic 



malate is of special interest. 



Other noteworthy results are the following : — 



20 hrs. 44 hrs. 



Ethylic acetate 075 0'7 



Ethylic butyrate 6"0 10-0 



Amylic acetate 2 - 5 4*5 



Ethylic malonate 5 - 5 8 - 



Ethylic dimethylmalonate 075 0'75 



Ethylic benzoate 075 1-0 



Methylic salicylate 05 0"5 



Ethylic mandelate 0*5 0'5 



Methylic oxalate — — 



The fact that amylic acetate, which is far less soluble in water than 

 ethylic acetate, is more susceptible to lipase is an interesting confirmation of 

 the explanation given above. 



As it appeared possible that the differences in the rates at which different 

 salts were hydrolysed might be due to the poisoning of the enzyme, the 

 finely ground seed residue was mixed with the ethereal salt and the mixture 

 shaken during an hour ; the solid was then filtered off, washed with ether 

 vol. lxxviii. — B. 2 G 



