Chapter VI D 



THE NICOTINIC ACID GROUP 



Specificity 



Although nicotinic acid was prepared synthetically in 1867 by the 

 oxidation of nicotine, 1, 2 - 3 it was not isolated from natural products until 

 1912.4, 5, c j n 1934^ nicotinamide was isolated from coenzyme II by War- 

 burg and Christian, 7 who thereby demonstrated the first biological role 

 of the factor since coenzyme II was recognized as a hydrogen-transporting 

 coenzyme. Euler, Albers, and Schlenk 8 shortly afterward obtained nico- 

 tinamide from coenzyme I. The structure of coenzyme I originally pro- 

 posed by Schlenk and Euler 9 is indicated as follows: 



N=C— NH 2 



r^N-CO-NH 2 H( L i_ N 



II J II II >CH 



x Nr N— C— N' 



H— 6 H— i- 



H— C— OH | H— C— < 



-OH 



H— C— OH I H— C— ( 



H-i- 



CH 2 — O- 



coenzyme I; cozymase 



Coenzyme II contains an additional phosphate group and can be converted 

 into coenzyme I. 10 The exact location of this phosphate group is still 

 questionable. 



The first indication of the importance of this group of factors in nutri- 

 tion was presented by A. Lwoff and M. Lwoff, 11 who demonstrated that 

 a factor essential for growth of certain bacteria of the Hemophilus 

 group, 12 - 13 the "V" factor, was replaced by either coenzyme I or II, both 

 of which possess properties analogous to those of the "V" factor. Shortly 

 thereafter, the role of nicotinic acid as an essential growth factor was 

 demonstrated for Staphylococcus aureus by Knight 14 and for Coryne- 

 bacterium diphtheriae by Mueller. 15 The activity of nicotinic acid and 

 nicotinamide in preventing blacktongue in dogs was subsequently demon- 



604 



