PHOTOSYNTHETIC PHOSPHORYLATION AND THE ENERGY CONVERSION PROCESS 



TABLE XVIII 



395 



Effect of Phenazine Methosulphate (PMS) on Phosphorylation and Oxygen 

 Evolution Linked to TPN Reduction 



(Arnon, Whatley, and Allen [158]) 



Reaction 4. Table XVII shows that the addition of as httle as 0-0002- 

 0-0005 /^rnoles of FMN or vitamin K increased ATP formation without 

 appreciably depressing oxygen evolution (and the corresponding TPNHg 

 accumulation). Similar eifects were observed on adding small amounts of 

 phenazine methosulphate (Table XVIII). 



-12 



10 ^ 



5: 

 3. 



10 20 10 



minutes 



Fig. 31. Photophosphorylation and oxygen evolution by isolated chloroplasts 

 in the presence and absence of vitamin K3 (Arnon, Whatley, and Allen [95, 158]). 



Non-cyclic photophosphorylation provides the three products of the 

 light phase of photosynthesis : O.,, TPNHo, and ATP. Cyclic photo- 

 phosphorylation supplies only ATP and the participation of this reaction 

 in COo assimilation would be needed only if the ATP formed in non- 

 cyclic photophosphorylation were insufficient for COo assimilation to the 

 level of carbohydrate. Evidence that this is indeed the case, and that both 



