368 



ENZYMES 



be sterilized by means of heat, so that antiseptics must be 

 added. Amongst those commonly employed are chloroform, 

 toluene, thymol, sodium fluoride, and hydrocyanic acid. The 

 nature of the antiseptic exerts a considerable influence upon 

 the activity of the enzyme used, so that it is necessary to try 

 many different antiseptics. The following table illustrates 

 this in the case of papai'n*: 



LIPASE. 



The existence of a fat-splitting enzyme or lipase in the 

 animal kingdom has long been known. This substance, which 

 is known as steapsin, is contained in the pancreas ; acting in 

 an alkaline medium it is able to break up fats into glycerol 

 and free fatty acids, the latter combining in the intestine with 

 alkali to form the sodium salts or soaps. Umeda f finds that 

 phosphates are the most active constituents of the coenzyme 

 of inactive lipase obtained from pancreatic extracts. 



In 1890 Green J found that germinating seeds containing 

 fat or oil, when macerated with water and left for some time, 

 gradually acquired an acid reaction. This observation was 

 subsequently confirmed and extended by Connstein, Hoyer, 



* Vines : " Ann. Bot," 1903, 17, 602. 



f Umeda : "Biochem. Journ.," 1915, 9, 38. 



J Green : " Proc. Roy. Soc., Lond.," 1890, 48, 375. 



