78 



SAPONIFIABLE LIPIDS 



Cephalin 



+ 

 + 



Both substances are hygroscopic but form emulsions rather than true solutions in water. 

 They may be precipitated from these solutions by adding acetone. In recent years, how- 

 ever, solvent fractionation methods of purification have been largely replaced by more 

 effective procedures. 



Other types of phospholipid have been found in plants, but much less is known 

 about them. Phosphatidyl glycerol and diphosphatidyl glycerol have been found as major 

 phospholipids in algae and higher plants, especially in chloroplasts (7, 8). 







II 



H^OCR 



8 I HgCOH 

 R'COCH ^1 



I CHOH 

 I t I 

 H2COPOCH2 



OH 





 II 

 H2COCR 







R'COCH 



OH 



t I t 



H2COPOCH2CHCH2OPOCH2 



OH HO 



8 



hcocr" 





 Rf'COCHg 



phosphatidyl glycerol 



diphosphatidyl glycerol 



An inositol-containing lipid isolated by Woolley (9) and named lipositol was probably not 

 pure but yielded on hydrolysis inositol, galactose, ethanolamine, oleic acid, phosphoric 

 acid, and tartaric acid. Wagenknecht e/ aZ. , (10) have isolated from peas the calcium- 

 magnesium salt of a phospholipid which is hydrolyzed to glycerol, inositol, phosphoric 

 acid, C16 and Cjg fatty acids. Phosphatidyl inositol makes up about 20% of the lipid of 

 photosynthetic tissues (10a). Soybean lipids also contain a large percentage of inositol 

 but are apparently more complex as indicated by the work of Carter et al. , (11, 12) who 

 found on hydrolysis fatty acids, inositol, phosphoric acid, several sugars including gluco- 

 samine and a uronic acid, and a nitrogen base named "phytosphingosine" since it is simi- 

 lar but not identical to the sphingosine of animal tissues. Phytosphingosine appears to 

 have the structure shown below: 



OH OH NH2 

 I I I 

 CH3(CH2)i3CH-CH-CHCH20H 



