563 



Pteridines and Flavincj 



H-f'-'U 



&0*-' 



zh^2nr:!Hz 2 



CYT 





+ 

 H 



Another hypothesis assumes close approach of DPNH 

 and riboflavin in parallel planes with interposition of in- 

 organic phosphate, held perhaps by hydrogen bonding, 

 e.g. to the amide moiety of nicotinamide.'^^ These geomet- 

 rical and chemical relationships can be represented as 

 follows : 



ie " 



"Barbro Grabe, Biochim. et Biophys. Acta 30 560 (1958). 



