LIPIDES 91 



(sphingosine), a fatty acid (usually lignoceric), phosphoric acid, and 

 choline. It has been shown that the fatty acid is attached to the amino 

 group of sphingosine to form an amide called lignoceryl sphingosine. 

 This substance, which can be formed by the partial hydrolysis of 

 sphingomyelin, is found in the spleen and liver of the pig. 



CH,(CH.,)i2CH=CH— CH— CH— CH2 



I 1 1 



OH NHo OH 



sphingosine (an amino alcohol) 



o 



NH— C— R 



CHsCCHs) i2CH=CH— CH— CH— CH2 



I I 



OH O 



I 



o=p— o- 



I 



o 



I 



(CH3)3NCH2CH2 



+ 



a sphingomyelin 



GLYCOLiPIDES (CEREBROSIDES) 



Compound lipides which hydrolyze to one fatty acid residue, 

 sphingosine or dihydrosphingosine, and glucose or galactose are 

 called glycolipides. Also called cerebrosides, these compounds occur 

 in relatively large amounts in brain tissue and in smaller amounts 

 in virtually every other organ of the body. Physically they are white 

 solids which are insoluble in ether and water but soluble in hot 

 alcohol and pyridine. In structure, the glycolipides are quite similar 

 to the sphingomyelins except that phosphoryl choline is replaced by 

 galactose or glucose. The fatty acids found in cerebrosides are prin- 

 cipally those containing 24 carbon atoms. For example, the cerebro- 

 side, kerasin, is a galactolipide containing lignoceric acid while 

 cerebron is a galactolipide containing hydroxylignoceric acid. 



Under certain pathological conditions (for example, Gaucher's 

 disease) large amounts of glucose-containing cerebrosides are deposited 

 in the spleen. Glucolipides are also found in small amounts as normal 

 constituents of almost every organ of the body. 



