THE CEPHALINS 443 



platiiuini chloride compound. Whereas the lecithin-cadmium chloride is 

 insoluble in ether, the opposite is true for the cephalin-cadmium chloride 

 salt. 



According to Thudichum,-®^ the lead salt of cephalin is soluble in ether 

 and insoluble in alcohol. However, Levene and West^^^-^^* found that a 

 purified lead salt, in the form of an amorphous yellow powder, is insoluble in 

 ether, alcohol, or acetone, but that it is dissolved more or less in benzene, 

 toluene, and pyridine. Its empirical formula was calculated as C41H74- 

 NPOi3Pb2.^®^ Cephalin reacts with nitrous acid by virtue of its amino 



P'T'Ol ID 255,265,266 



Because of its unsaturated component fatty acids, cephalin will readily 

 add bromine. The iodine number of the preparation of Frankel and Neu- 

 bauer-" was 80, while that of Wagner^" was 40.7. The addition of hydro- 

 gen with a palladium catalyst proceeds somewhat unsatisfactorily. ^^^•^'^^•"•'^ 

 Hydrocephalin has a formula of C41H82NPO8 and a specific rotation in chlo- 

 roform of +6.0°. The phosphatide itself exhibits a slight levo-rotation in 

 chloroform, although a somewhat less pure preparation has been reported to 

 show a strong dextro-rotatory activity in petroleum ether {[a]^ = + 13.6°) . 

 Cephalin acts as a fairly strong acid, in contrast to the behavior of lecithin, 

 which acts as a base. Cephalin is susceptible to autoxidation, especially in 

 the presence of ferric chloride. 



Cephalin is able to form stable compounds with proteins under certain 

 conditions where neither lecithin nor sphingomyelin will react. Chargaff-'^'' 

 prepared a stable salmine-cephalin compound at pH ranges from 2 to 11 

 which was believed to be a water-insoluble salt between the strongly basic 

 protamme and the acidic phosphatide. The salt had a composition of 80% 

 of cephalin and 20% of salmine. Although with strongly alkaline buffers 

 an insoluble compound was formed with lecithin, no such combination ob- 

 tains within the physiological range. Chargaff ^'^^ was also able to synthe- 

 size a similar insoluble salt with egg albumin at a pH of 2, 3, or 4. It would 

 appear that this ability of cephalin to react is related to the position of the 

 isoelectric point of the protein, which is 12 in the case of salmine^^^ and 4.8 

 for egg albumin. ^^^ 



On heating with water, weakly basic or acidic solutions, phosphatidyleth- 



2«s P. A. Levene and C. J. West, J. Biol. Chem., 24, 41-53 (1916). 

 ^* P. A. Levene and C. J. West, J. Biol. Chem., 24, 111-116 (1916). 

 2« A. Baumann, Biochem. Z.,54, 30-39 (1913). 

 2«« G. Trier, Z. pht/siol. Chem., 86, 141-152 (1913). 

 2«' R. Wagner, Biochem. Z., 64, 72-81 (1914). 



26« P. A. Levene and C. J. West, /. Biol. Chem., 25, 517-519 (1916). . 

 '«» P. A. Levene and S. Komatsu, J. Biol. Chem., 39, 91-104 (1919). 

 ^'o E. Chargaff, J. Biol. Chem., 125, 661-670 (1938). 

 "I S. Miyake, Z. phijsiol. Chem., 172, 225-229 (1927). 



"* C. L. A. Scliinidt, in AI. Saliyun, Onlline of the Amino Acids and Proteins, Reinliold, 

 New York, 1944, pp. 41-72. 



