406 FORMATION OF FAT FROM PROTEIN 



Dakin's observation that the racemic esters of mandelic 



C*H 



acid, I are asymmetrically split by the lipase 



CH(OH).COOH' 



from hog's liver has been interpreted to mean that the 

 enzyme itself is an optically active substance. 19 



It is worth noting, too, that the tissue lipases, just as the 

 pancreatic lipase, may be activated by biliary salts. 20 More- 

 over, the fact that minute amounts of acid serve to activate 

 a tissue lipase of vegetable nature, the lipase of ricinus, has 

 proved of very wide practical value in industrial fat cleav- 

 age, based on the studies of Connstein, Hoyer and Water- 

 berg. 21 The same ferment, which brings about cleavage of 

 neutral fat in the presence of an excess of water, works 

 in the reverse fashion, that is, to cause synthetic formation 

 of neutral fat, when allowed to act upon a mixture of fatty 

 acids and glycerol in a medium poor in water. 22 



FORMATION OF FAT FROM PROTEIN. FATTY DEGENERA- 

 TION AND FATTY INFILTRATION 



At this point we turn to a difficult and complicated 

 problem which has had a prime position for the past half 

 century in the interest of metabolic physiologists and pathol- 

 ogists, the question of formation of fat from protein. 



The doctrine of a metamorphosis of protein into fat takes 

 its starting-point on the one hand from E. Virchow 's micro- 

 scopic observations upon fatty degeneration of tissues, and 

 on the other from metabolic investigations. 23 



In the years from 1862 to 1871 Carl Voit in association 



19 Dakin, Jour, of Physiol., 32, 199, 1905. 



A. S. Loevenhart (Johns Hopkins Univ.), Jour, of Biol. Chem., 2, 391, 

 415, 1907. 



* E. Hoyer, Zeitschr. f. physiol. Chemie, 50, 414, 1907. 



22 Cf. A. Welter, Zeitschr. f. angew. Chem., 24, 385, 1911, cited in Chem. 

 Centralbl., 1911', 1258. 



23 Literature upon Fat Formation from Protein in Metabolism : G. Rosen- 

 feld, Ergebn. d. Physiol., 1, 655-699, 1902; R. Tigerstedt, Nagel's Handb. d. 

 Physiol., 1, 511-512, 1905; A. Magnus-Levy and L. F. Meyer, Handb. d. 

 Biochem., 4', 451-453, 1909. 



