376 



Studies on Enzyme Action. — Lipase : II. 



By Henry E. Armstrong, F.B.S., and Ernest Ormerod, PhD., M.Sc. (Vict.), 

 Salters' Company's Besearch Fellow, Chemical Department, City and 

 Guilds of London Institute, Central Technical College. 



(Beceived and read June 14, 1906.) 



[International Catalogue of Scientific Literature. 



Author's title slip : — D. Q. 



Subject slips : — 

 D 7090 Q 1230 Hydrolysis by Lipase* 

 D 8014 Q 1240 Ricinus and Liver Lipase.] 



The following account has reference to the pursuance of the inquiry into 

 the nature of the process whereby the fats are hydrolysed under the influence 

 of lipase* ; the experiments have been made in the hope of discovering an 

 explanation of the selective power which the enzyme undoubtedly displays, 

 as it promotes by preference the hydrolysis of ethereal salts of the higher 

 fatty acids such as are present in the natural fats. 



The active material used, as a rule, has been the finely ground air-dried 

 residue which is left on depriving crashed castor oil seed of oil by means of 

 ether ; although but slightly active towards ethereal salts other than fats, it 

 is easily prepared of uniform quality and does not soon deteriorate when kept. 

 In all cases, the effect produced in blank control experiments is allowed 

 for. As a rule hydrolysis took place at the temperature of the laboratory. 



Operating with what appear to have been highly active materials, Kastle 

 and Loevenhartf were able by means of hepatic and pancreatic lipase to 

 effect the hydrolysis of several ethereal salts derived from the lowest terms 

 of the acetic series of acids. The results they obtained in two series of 

 experiments are as follows, the figures representing the percentage amount of 

 salt hydrolysed after 15 minutes at 40° : — 



As the formate is readily attacked by water alone, they regarded the 

 values for this salt as high ; unfortunately they made no control experiments 



* Part I, see 'Roy. Soc. Proc.,' B, vol. 76, p. 606. 



+ Loc. cit. We have not yet had the opportunity of consulting Kastle's recent 

 publication. 



Ethylic formate . . . 

 „ acetate . . . 

 „ propionate 

 „ butyrate... 



1-60 



0- 93 



1- 05 

 313 



1-75 



1- 75 



2- 87 

 4-37 



