NICOTINAMIDE NUCLEOTIDE ENZYMES 



127 



formation of the codehydrogenases from nicotinamide in the or- 

 ganism. The biological function of the nicotinamide-containing 

 coenzymes and their wide distribution in nature (If) were known 

 before their vitamin properties. There was little doubt that the 

 nicotinamide ingested as a vitamin is used to form the coenzymes. 

 Nevertheless an exact demonstration had to be obtained. 



k^ 



1.6 



1.2 - 



0.8 



0.4 



Protein II added 



Mi N. 



Figure 3. — Action of oxidizing and reducing fermentation enzymes. Spectro- 

 photometric experiment, absorption at 340 m\i ( dihydrocozymase ) . d = 0.557 

 cm. Protein I: diphosphoglyceraldehyde apodehydrogenase. Protein II: acetal- 

 dehyde reductase (alcohol apodehydrogenase). The concentrations are as 

 follows: cozymase, 0.183 mg. per ml.; (i-phosphoglyceraldehyde, 0.733 mg. per 

 ml.; acetaldehyde, 1.47 mg. per ml.; apoenzymes (protein I and II), 0.0008 mg. 

 per ml.; orthophosphate, 3.3 X 10 '^ mole per ml.; pyrophosphate, 3.3 X 10"' 

 mole per ml. 



Experiments on animal tissues were performed by Axelrod and 

 Elvehjem. The cozymase level of pigs and dogs living on a diet low 

 in nicotinamide was found to be decreased in muscle and liver. 

 Upon administration of nicotinamide the normal cozymase content 

 was rapidly restored (56). Later the same effect was observed in 

 pellagrins by Axelrod, Spies, and Elvehjem (58). Experiments on 

 rats also seemed to indicate the same result (57), but according 



