58 THE SIMPLER NATURAL BASES 



Amino-ethyl Alcohol (Colamine) and the Origin of Choline; the 

 Possible Presence of other Bases in Phosphatides. 



By the hydrolysis of kephalin (a phosphatide from the brain) by 

 means of baryta, Thudichum [1884, 1901] obtained long ago, in ad- 

 dition to choline, a base having the composition of "oxethylamin," 



NH a .CH 2 .CH 3 OH. 



During the last few years Trier has isolated a base of the same com- 

 position from lecithin of various sources and has definitely identified it 

 as hydroxy-ethylamine or amino-ethyl alcohol. By hydrolysis of the 

 phosphatide from beans (Phaseolus vulgaris) Trier [iQll] obtained 

 a fraction, representing one-seventh of the nitrogen content of the 

 phosphatide, which yielded an aurichloride C 2 H 5 ON . HAuCl 4 , 

 identical with that of a base previously synthesised by Knorr from 

 ammonia and ethylene oxide : 



CH 2 \ CH 2 OH 



NH 3 + | )0 = | 



CH 2 / CH 2 NH 2 . 



The same base was subsequently obtained from the lecithin of peas 

 and oats and also from commercial ovolecithin of Merck (Trier [1912, i]). 



The amino-ethyl alcohol can be estimated in phosphatides by means 

 of Van Slyke's method (see Plimmer's " Chemical Constitution of the 

 Proteins," Part I, p. 69). Trier [1913, 2] concludes from this that the 

 base is joined to the rest of the phosphatide molecule by means of its 

 hydroxyl group. In one specimen of ovolecithin the amino-nitrogen 

 was nearly half the total. 



Baumann [1913] and Renall [1913] also used Van Slyke's method 

 and showed that kephalin from human brain and from that of the 

 sheep and ox contains as only base amino-ethyl alcohol and that here 

 too the primary amino-group is free. They could not find choline and 

 another base, which Thudichum believed to accompany the amino- 

 ethyl alcohol. 



Trier considers that choline is formed from amino-ethyl alcohol 

 by the biologically common process of methylation, in the same way 

 that the betaines are derived from amino-acids. Thus there would be 

 no genetic relationship between choline and betaine. 



The question is then : How is amino-ethyl alcohol itself formed ? 

 Winterstein and Trier [1909, p. 311]* put forward the hypothesis 

 that formaldehyde is condensed to glycollic aldehyde and that the 

 latter is converted by ammonia into amino-acetaldehyde. By simul- 



1 This and the subsequent references in this section will be found in the bibliography 

 under choline. 



