ENZYMES CONCERNED WITH DIGESTION OF LIPIDS 11 



duct, while no concomitant rise in blood esterase obtains. On the other 

 hand, Glotzer and Seligman 48 reported that the blood of normal dogs con- 

 tains an appreciable concentration of lipase. By the end of the first week 

 after pancreatectomy, serum lipase showed a marked decrease, which was 

 maintained over several Aveeks, after which some increase was observed. 



e. Ricinus Lipase (Castor-Bean Lipase). As early as 1890, Green 49 and 

 also Sigmund 50 discovered that the germinating seeds of the castor-bean 

 plant (Ricinus communis), of the summer rape (Brassica napus annua), 

 and of the oil-producing winter rape, or colza (B. napus oleifera), possess a 

 powerful lipase. It was first believed that ricinus lipase occurs in the form 

 of a zymogen, and that it becomes activated in the germinating seeds of the 

 castor-bean by the formation of acid. This idea was refuted by Connstein 

 and collaborators, 51 who showed that castor-bean preparations which had 

 been acidified and then neutralized possessed no greater lipolytic action 

 than did control preparations treated with distilled water. This enzyme 

 was shown to be a true lipase, inasmuch as its main action is on neutral 

 fats. Although it has been reported to have little action on the lower 

 esters, 52,63 Willstatter and Waldschmidt-Leitz 54 stated that the enzyme 

 exerts an equally effective action as a lipase and as an esterase. Falk and 

 Sugiura 55 had demonstrated earlier that the lipase and esterase properties 

 of the castor-bean enzymes could be separated by virtue of differences in 

 solubility. Both fractions were found to be proteins. Cholesterol esters 

 apparently cannot be hydrolyzed by the lipase preparation from castor- 

 bean. 56 



Willstatter and Waldschmidt-Leitz 54 denied the possibility that an ester- 

 ase and a lipase can be separated into two components; they state that 

 their lipase, which possesses both triglyceride- and ester-hydrolyzing prop- 

 erties, is a pure preparation. Longenecker and Haley 57 reported that 

 ricinus lipase exhibits no specificity insofar as the triglyceride linkage is 

 concerned, and that it brings about a similar degree of lipolysis regardless 

 of the chain length of the fatty acids involved. In the case of natural fats, 



48 P. Glotzer and A. M. Seligman, Am. J. Physiol., 164, 486-489 (1951). 



49 J. R. Green, Proc. Roy. Soc. London, 48, 370-392 (1890). 

 80 W. Sigmund, Monatsh., 11, 272-276 (1890). 



61 W. Connstein, E. Hoyer, and H. Wartenberg, Ber., 35, 3988-4006 (1902). 

 52 H. E. Armstrong, Proc. Roy. Soc. London, B76, 606-608 (1905). 



63 K. G. Falk, J. Am. Chem,. Soc, 85, 1904-1915 (1913). 



64 R. Willstatter and E. Waldschmidt-Leitz, Z. physiol. Chem., 184, 161-223 (1923- 

 1924). 



88 K. G. Falk and K. Sugiura, J. Am. Chem. Soc, 87, 217-230 (1915). 



86 F. E. Kelsey, J. Biol. Chem., 130, 199-202 (1939). 



57 H. E. Longenecker and D. E. Haley, /. Am. Chem. Soc, 57, 2019-2021 (1935). 



