PHOSPHATIDES 407 



phosphatides. Other summaries include the classical and comprehensive 

 review of Levene and Rolf,^ which deals with the structure and significance 

 of the phosphatides. The review of Working and Andrews' is confined 

 to a discussion of structure, while the latest treatise of Thannhauser and 

 Schmidt^" on lipins and lipidoses contahis an excellent description of our 

 present chemical concept of structure and classification. The application 

 of labelling agents in the study of phospholipid metabolism is the subject 

 of an interesting report by Chaikoff.^^ 



2. Historical Development 



The first proof of the existence of complex fatty compounds is generally 

 credited to Fourcroy,^^ whose experiments were reported as early as 1793; 

 Vauquelin/^ however, was the initial investigator to prove the presence 

 of bound phosphorus in the fat-like material of the brain. The work of 

 Gobley^^"^^ was particularly outstanding, since it demonstrated for the 

 first time the presence of a phosphatide in egg-yolk. This substance was 

 later christened lecithin after the Greek equivalent of egg-yolk, XeKidos. 

 A further ad\"ance in our appreciation of the composition of at least one 

 phosphatide, lecithin, ^^ followed the demonstration, in Hoppe-Seyler's 

 laboratory in Tiibingen, by Diakonow,^*-^' that choline is its nitrogenous 

 component. Strecker-" had prepared this compound several years earlier 

 from hog bile. Diakonow^^-^^ and Strecker^^ were also able to show that 

 the lecithin molecule was composed of two molecules of fatty acid, either 

 similar or different; these were esterified with glycerol, which was also 

 identified. Thudichum-^ was the first to differentiate cephalin from 

 lecithin by separation of the two phosphatides in alcohol. Cephalin is 



« P. A. Levene and I. P. Rolf, Physiol Revs., 1, 327-393 (1921). 



9 E. B. Working and A. C. Andrews, Chem. Revs., 29, 245-256 (1941). 



10 S. J. Thannhauser and G. Schmidt, Physiol. Revs., 26, 275-317 (1946). 



11 1. L. Chaikoff, Physiol. Revs., 22, 291-317 (1942), 



12 E. Fourcroy, Ann. chim., 16, 282-.322 (1793). Cited by E. G. Working and A. C. 

 Andrews, Chem. Revs., 29, 245 (1941). 



1' M. Vauquelin, Ann. chim., 81, 37-51 (1812). 



1^ M. Goblev, /. pharm. chim. [3], 9, 1-15, 81-91, 161-174 (1846). 



15 M. Goblev, J. pharm. chim. [3], 11, 409-417 (1847). 



i« M. Gobley, ./. pharm. chim. [3], 12, 1-13 (1847). 



'- C. Diakonow, Med.-Chem. Unlersitch., (F. lloppe-Sevler), 2, 221-227 (1867); 3, 

 405-411 (1868). 



18 C. Diakonow, Zentr. Med. Wiss., 6, No. 1, 2-3 (1868). 



15 C. Diakonow, Zentr. Med. Wiss., 6, No. 7, 97-99 (1868). , 



20 A. Streoker, Ann., 123, 353-360 (1862). 



21 C. Diakonow, Zentr. Med. Wiss., 6, No. 28, 434-435 (1868). 

 " A. Streckcr, Ann., US, 77-90 (1868). 



2' J. ^\'. L. Thudichum, .4 Treatise on the Chemical Constitution of Brain, Bailliere, 

 Tiiidall and Cox, London ( 1884 ). Cited by H. Thierfelder and E. Klenk, Die Chemie der 

 Cercl>roside und Phosphatide, Springer, Berlin, 1930, pp. 65 ff. 



