ERYTHROCYTES 



267 



entering into relationship with the anionic end groups of the protein 

 (layer III). Haemolysis experiments have further shown how calcium 

 ions consolidate the erythrocyte membrane and stabiHze it. In layer II 

 the calcium ions, with their strong positive charge, are therefore 

 allocated between the negative phosphoric acid groups of the lecithin 

 and a more powerful ionogenic 



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YL 



280i 



i)^i^i^i^»C c 



qF 



M 

 E 



mn-i^-rom^i^Hi 



/ 



20& 



cohesion is thereby attained. Thus 

 the stroma is regarded as a com- 

 plex system consisting of phos- 

 phatide-calcium ions, stromatin 

 protein, and the regular distri- 

 bution of charge brings with it a 

 definite arrangement and orien- 

 tation of the various components m ^2o^\ 

 of the system. The tricomplex sys- 

 tem is completed by an assumed 

 complex linkage of the haemo- 

 globin (layer VI) with anionic 

 end groups in layer V to cationic 

 groups of the stromatin. 



The design of Fig. 1 3 3 is further 

 complicated by layer A. This re- 

 presents an incomplete film of 

 polar lipids, which turn their lipo- 

 philic side towards the monomo- 

 lecular phosphatide layer I and 

 their hydrophilic pole outwards 

 (fat, fatty acids, possibly chole- 

 sterol). It is necessary to assume this, for, without the layer A, the 

 erythrocytes would agglutinate in aqueous solutions and, when 

 shaken out with paraffin oil, would pass over into the lipid phase, 

 neither of which they do. 



The scheme devised by Winkler and Bungenberg de Jong (1941) 

 explains manv properties of erythrocytes, e.g., it makes allowance for 

 the lipid filter theory of permeability, there being a fipid film with 

 molecular pores (where the cholesterin covering is lacking). It ex- 

 plains the permeability to anions which is characteristic of erythro- 

 cvtes, as the calcium ion layer III debars the cations. The same layer 



Fig. 133. Molecular structure of the en- 

 velope of the red cell from Winkler and 

 Bungenberg DE Jong (i940-'4i); • anionic 

 groups ; o cationic groups or cations (Ca) ; 

 shaded: cholesterin; ^ phospholipid acid; 

 ch cholesterin ester; • fatty acid. 



