HYDROLYSIS OF PHOSPHOLIPIDS 



237 



tain a glycerol component in its molecule. Goebcl^ reported that 



Phosphatidj'lethanolamine > Lysocephalin 



Lj'socephalin > Glycerylphosphorylethanolamine 



Glycerj'lphosphorylethanolamine > L-a-glycerylphosphate + ethanolamine 



The Postulated Course of the Metabolism of Cephalin by Enzj-me Preparations of 



Serralia plymuthicum^ 



sphingomyelin, which had been injected into rabbits and mice, dis- 

 appeared from the blood, within a relatively short time, which varied 

 with the dose injected. Although a temporary increase in the sphingo- 

 myelin content of different organs, and particularly of the liver, resulted, 

 the increase lasted only a short time, and the level of acid-soluble phos- 

 phorus in the blood was raised. It was concluded that the destruction of 

 sphingomyelin proceeds first through the cleavage of phosphoric acid. In 

 a later study, Goebel and Seckfort^" found that human brain and liver were 

 both able to effect the hydrolysis of sphingomyelin. The optimal pH was 

 7.2 in the liver and 6.2 in the brain. The reaction progressed about three 

 times as rapidly in the liver as in the brain. Here again phosphoric acid 

 was identified as one of the decomposition products, perhaps the only one. 

 In a more complete study of the hydrolysis of sphingomyelins, Fujino^^ 

 suggested the following possibilities for the breakdo^^•n of sphingomyelin : 



H NHCOROH 

 CH3 • (CH2),2 • CH : CH • C • CH • CH2OP— O— (CH2)2N(CH3)3 • OH 

 OH O 



Sphingomyelin 



Sphingomyelinase 



H NHCOR OH 



I I I 



CH3-{CH2)i2-CH:CH-CCH-CH20H + HOP-0-(CH2>-N(CH3)30H 



I II 



OH O 



Ceramide Phosphorylcholine 



H3PO4 + HOCH2CH2X(CH3)3 0H 

 Phosphoric Choline 



acid 



The Hydrolysis of Sphingomyelin as Adapted from Fujino" 



^ A. Goebel, Biochem. Z., 319, 196-202 (1948). 

 1" A. Goebel and H. Seckfort, Biochem. Z., 319, 203-208 (1948). 

 " Y. Fujico, /. Biochem. (Japan), 39, 55-62 (1952). 



