LIFASE 367 



the seeds of Euphorbiaceae, and especially castor-oil seeds, 

 whether germinating or not, contain an enzyme capable of 

 hydrolysing not only the fat present in such seeds but also 

 fats from other sources. The observation that the hydrolysis 

 takes place slowly at first and then suddenly increases from 

 5 per cent after one day to 58 per cent after two days and to 

 95 per cent after four days led the authors to the conclusion 

 that for rapid hydrolysis a certain minimum amount of free 

 acid must be present, and it was found that when a little free 

 acid was added from the commencement hydrolysis could be 

 completed within a few hours. Similar observations regarding 

 the curve of the hydrolysis of fats during the germination of 

 Ricinus seeds have been made by Delcano.* 



According to Nicloux f fats may be attacked by other 

 means. He used castor-oil seeds, which were ground up and 

 the cytoplasm separated from the aleurone grains and other 

 cell contents by mechanical means. 



It was found that the cytoplasm thus prepared showed a 

 marked power of hydrolysing fats, acting in the same way as 

 an enzyme and obeying the laws of enzyme action. But inas- 

 much as the active substance, which Nicloux calls lipase'fdine, 

 contained in the protoplasm is destroyed by water as soon as 

 its protective layer of fat is removed, it is not considered to be 

 an enzyme in the ordinary sense of the term. 



The most favourable conditions for the activity of lipase 

 may be summarized as follows : 



(a) The presence of free acid varying from N/6o to N/ioo 

 or less, according to the amount of material to be hydrolysed. 



(fr) The presence of a certain amount of water. 



(c) The formation of a good emulsion. 



(d) The maintenance of a suitable optimum temperature, 

 varying from about 23 to 42 C. 



THE ISOLATION OF LIPASE. 



Lipase may be separated from the seeds of Ricinus by the 

 following means : The seeds are allowed to begin germination ; 

 when the radicles have protruded a little way, the endosperms 

 are ground in a mortar with a 5 per cent solution of sodium 



* Delcano: "Centrlbl. Bakt.," 1909, 24, 130. 



f Nicloux : " Proc. Roy. Soc., Lond.," B., 1906, 77, 454. 



