444 V, CHEMISTRY OF PHOSPHATIDES AND CEREBROSIDES 



anolamine can be hydrolyzed to fatty acids, glycerophosphoric acid, and 

 colamine. Hydrolysis with barium hydroxide proceeds very slowly, in 

 contradistinction to the reaction between alkali and lecithin. While leci- 

 thin is hydrolyzed to the extent of 90% merely by shaking with a saturated 

 barium hydroxide solution at room temperature for 16 hours, phosphatidyl- 

 ethanolamine under similar conditions is split only to the extent of 19%. 

 Levene and Rolf ^^^ have likewise sho^\^l the difficulty of preparing nitrogen- 

 free glycerophosphoric acid from cephalin. Complete hydrolysis of cepha- 

 lin occurs when the solution is boiled for 2 to 3 hours with 6% hydrochloric 

 acid,"'^ or on continuous agitation of a 50-g. sample of cephalin at 60°C. with 

 a mixture of 300 ml. of a 20% sulfuric acid solution or a mixture of 75 g. of 

 cephalin in 250 ml. of water and 550 ml. of concentrated hydrochloric 

 acid.^^^ In spite of the difficult hydrolysis with barium hydroxide, there 

 seems to be little evidence that phosphatidylethanolamine is more difficultly 

 hydrolyzable with other hydrolyzing agents than is lecithin. There is no 

 apparent mechanism of enzymatic destruction or hydrolysis of cephalin. A 

 breakdown may possibly be caused by a non-specific esterase, but such a re- 

 action has not as yet been demonstrated. 



e. Lysocephalin. Although the snake venoms bring about profound 

 changes in the cephalin molecule, the proof of the nature of the lyso- 

 cephalin molecule so produced is not so clear-cut as is the case with lyso- 

 lecithin. Lysocephalin produced by cobra venom has too low a carbon 

 value to correspond to the theory for monostearocephalin, and the ash 

 content is especially high. 



Lysocephalin has been shown to form a definite part of the lysophospha- 

 tides produced b}' snake venoms. After cephalin had been acted on by co- 

 bra venom {Naja flava), lysocephalin was found to comprise 22%^* and 

 20% 100 of the total lysophosphatides ; after treatment with fer-de-lance 

 venom (Bothrops airox), the corresponding amounts of lysocephalin found 

 were 23^^ and 24.5%,^"'' while after the action of water-moccasin venom 

 (Ancistrodon piscivorus) the values varied between 30 and 32%.^"" Char- 

 gaff and Cohen ^'"^ have sho^\^l that purified preparations of lysocephalins 

 have no effect upon blood clotting, in marked contrast to the great activity 

 exhibited by untreated cephalin. This is in line with the earlier report of 

 Billing,"* who demonstrated that the thromboplastic effect of cephalin emul- 

 sions was destroyed by Croialus adamanieus venom (diamond-back rattle- 

 snake), and also with the observation"*-"^ that "cytozyme" is similarly in- 

 activated by cobra venom {Naja iripudians, N. flava). Since it is known 



2" H. Cousin, J. pharm. chim. [6], 24, 101-108 (1906). 

 27* W. M. Billing, J. Pharmacol, 38, 173-196 (1930). 

 "5 L. Hirschfeld and R. Klinger, Biochem. Z., 70, 398-415 (1915). 

 "6 T. Link, Z. Immunitdts., 85, 504-512 (1935); Zentr. Bakl. Parasilenk., I, 120, 396 

 ( 1936); Chem. AhsL, 30, 1435 (1936). 



