ANALOGUES 



19. J. McGinnis, L. C. Norris and G. F. Heuser, Proc. Soc. Exp. Biol. 



Med., 1942, 51, 293. 



20. J. McGinnis, L. C. Nonis and G. F. Heuser, ibid., 1944, 56, 197. 



21. V. du Vigneaud, S. Simmonds, J. F. Chandler and M. Cohn, /. 



Biol. Chem., 1946, 165, 639. 



22. V. du Vigneaud, S. Simmonds and M. Cohn, ibid., 1946, 166, 47. 

 22a. J. W. Dubnoff and H. Borsook, ibid., 1948, 176, 789. 



23. W. H. Griffith and D. J. Mulford, /. Nutrition, 1941, 21, 633. 



24. J. C. Forbes, ibid., 1941, 22, 359. 



25. C. S. McArthur, Science, 1946, 104, 222. 



26. D. B. Zilversmit, C. Entenman and I. L. Chaikoff, /. Biol. Chem., 



1948, 176, 193 ; C. Artom and W. E. Comatzer, ibid., 949. 



27. C. Artom, W. E. Comatzer and M. Crowder, ibid., 1949, 180, 495- 



28. I. L. Chaikoff, C. Entenman and M. L. Montgomery, /. Biol. 



Chem., 1945, 160, 489. 



14. ANALOGUES OF CHOLINE 



The only compounds, other than choline or betaine, that supported 

 the growth of young rats on a diet free from methionine but containing 

 homocystine were simple derivatives of choline, such as lecithin and 

 phosphorylcholine, and ethyl -^- hydroxy ethyldimethylammonium 

 chloride.^ Another homologue of choline, diethyl-j3-hydroxyethyl- 

 m.ethylammonium chloride prevented perosis in chicks, but did not 

 promote growth, whilst the triethylanalogue, triethyl-^-hydroxyethyl- 

 ammonium chloride, was neither anti-perotic nor growth-promoting.^ 

 Betaine was inactive in both respects, but the corresponding aldehyde 

 had a weak growth-promoting and anti-perotic activity. ^ The triethyl 

 compound, however, prevented renal haemorrhage in rats ^ and was 

 lipotropic, being incorporated, like choline, into the phospholipid 

 molecule.* 



A particularly interesting analogue of choline is ^-hydroxyethyl- 

 trimethyl-arsonium chloride, the so-called arsenocholine : 

 (CH3)3As . CH2 . CH2OH 



This compound was not able to methylate homocystine either in the 

 rat 1 or the chick, ^ but it had lipotropic activity ^ and promoted 

 growth and prevented perosis in chicks.'' ® Apparently, therefore, it 

 could replace choline in every function except that of transmethylation. 

 The result emphasises the variety of functions possessed by choline. 



Sulfocholine, /S-hydroxyethyl-dimethyl sulphonium chloride, be- 

 haved in a similar way to arsenocholine and, although unable to 

 methylate homocystine, it prevented fatty liver formation and renal 

 haemorrhages in rats fed a methyl-free diet.®" Since dimethyl 



603 



