74 



KARL FOLKERS 



During these independent researches on the nutrition of monkeys, 

 chicks, and microorganisms, there were indications that some of the 

 studies were concerned with a single entity, but were of unproven rela- 

 tionship during the early work. 



The last few months have marked the beginning of the clarification 

 of the chemical structural relationships between some of the factors 

 which appear to be chemically related to folic acid. 



Recent papers presented at the New York Academy of Sciences 

 and published in Science showed that the liver "L. casei factor" is 

 A^ [4{( [2-amino-4-hydroxy-6-pteridyl] methyl) amino}-benzoyl] glu- 

 tamic acid. The name pteroylglutamic acid has been suggested as a more 

 convenient designation for this new vitamin. These elucidations of 



TABLE III 

 Pteroylglutamic Acid 



Liver "L. casei" factor 

 Stokstad (1943) 



N N 



/\./Xnh, 



\ 



/ NHCH. ^;^^ 



N 



N 



OH 



Pteroylglutamic acid 



Vitamin Be 



Hogan and Parrott (1940) 



Isolation, Pfiffner and coworkers (1943) 



