II. CHEMISTRY 453 



lated nicotinic acid from yeast. However, none of these investigators real- 

 ized the true biological significance of the substance they had isolated. 



The first demonstration of a biochemical function for this substance 

 came from the work of Warburg and Christian'*' ^ who isolated nicotinamide 

 from coenzjTiie II (TPN) and demonstrated its function as part of a hy- 

 drogen-transporting coenzyme.^' "^ Almost at the same time von Euler et 

 alJ' isolated a substance from coenzyme I which was identified as nicotina- 

 mide (see p. 482). Coenzyme I (DPN, cozymase) had long been known as 

 a substance necessary for the alcoholic fermentation of carbohydrates by 

 yeast. Kuhn and Vetter^ further established the potential importance of 

 nicotinamide in metabolism by isolating it from heart muscle. 



The true nutritional and biological significance of nicotinic acid became 

 evident in 1937 following the reports of Elvehjem et al}° that it would cure 

 blacktongue in dogs and that nicotinamide could be isolated from hver 

 concentrates which were active in curing canine blacktongue.^^ The activity 

 of nicotinic acid in curing blacktongue was quickly confirmed by Street 

 and Cowgill."^ Late in 1937 Spies et al.,^- Fonts et al.,^^ and Smith et al.,^^ 

 almost simultaneously announced that nicotinic acid would cure pellagra, 

 a fact confirmed by innumerable reports since that time. The rather uni- 

 versal biological significance of nicotinic acid was further confirmed by the 

 reports of Knight,i^ Mueller,i^ Koser et al," Fildes,^^ and Landy^^ in 1937 

 and 1938, showing that this substance was an essential growth factor for 

 a variety of bacteria. 



^0. Warburg and W. Christian, Biochem. Z. 274, 112 (1934). 



5 O. Warburg and W. Christian, Biochem. Z. 275, 112, 464 (1935). 



" O. Warburg, W. Christian, and W. Griese, Biochem. Z. 282, 157, (1935). 



^ O. Warburg and W. Christian, Biochem. Z. 287, 291 (1936) 



* H. von Euler, H. Albers, and F. Schlenk, Hoppe-Seyler's Z. physiol. Chem. 237, 



180 I (1935); 240, 113 (1936). 

 9 R. Kuhn and H. Vetter, Ber. 68, 2374 (1935). 

 '» C. A. Elvehjem, R. J. Madden, F. M. Strong, and D. W. Woolley, ./. Am. Chem. 



Soc. 59, 1767 (1937); J. Biol. Chem. 123, 137 (1938). 

 " C. J. Koehn, Jr., and C. A. Elvehjem, ./. Nutrition 11, 67 (1936). 

 "» H. R. Street and G. R. Cowgill, Proc. Soc. Exptl. Biol. Med. 37, 547 (1937). 

 ^'^ T. D. Spies, C. Cooper, and M. A. Blankenhorn, Paper presented before the Cen- 

 tral Society for Clinical Research, Chicago, 111., November 5, 1937; J. Am. Med. 

 Assoc. 110, 622 (1938). 

 " P. J. Fouts, O. M. Helmer, S. Lepkovsky, and T. H. Jukes, Proc. Soc. Exptl. Biol. 



Med. 37, 405 (1937). 

 '* D. T. Smith, J. M. Ruffin, and S. G. Smith, /. Am. Med. Assoc. 109, 2054 (1937). 

 " B. C. J. G. Knight, Biochem. J. 31, 731 (1937). 

 '« J. H. Mueller, J. Biol. Chem. 120, 219 (1937). 

 "S. A. Koser, A. Dorfman, and F. Saunders, Proc. Soc. Exptl. Biol. Med. 38, 311 



(1938). 

 '« P. Fildes, Brit. J. Exptl. Pathol. 19, 239 (1938). 

 '« M. Landy, Proc. Soc. Exptl. Biol. Med. 38, 504 (1938). 



