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Discussion 



Jagexdorf: It seems to me that there is a chance that Krogmann's data on the 

 oxygen-requiring phosphorylation with a dye could still be explained if high 

 concentrations of the dye were really an uncoupler and the function of the ascorbate 

 is to maintain the dye in the reduced fomi so that you have a little bit of the 

 oxidized dye to be an acceptor in the usual scheme making ATP. I think you may 

 be able either to rule this out or prove it one way or the other, by experiments with 

 the indophenol dye and ferricyanide. Were you able to see stoicheiometric phos- 

 phorylation during the reduction of a mixture of a catalytic amount of the dye and 

 a lot of ferricyanide ? 



Vennesland : We have seen no ATP synthesis with the dye-ferricyanide 

 combination. I should mention that the grana which we were using had been 

 incubated for several hours at 20 in dilute suspensions and would probably not 

 make ATP with any cofactor. When they are fresh they can make ATP with 

 ferricyanide. I do agree with you that there are alternative ways of explaining the 

 phenomena. I think that we must still be ver\- flexible in our views. The mechanism 

 presented is the best working hypothesis at the present time. 



Smith : Is the intermediate compound between COo and formate phos- 

 phorylated or is it a peroxyformate ? 



Vennesl.^nd : The intermediate which Warburg postulates is a phosphate of a 

 peroxide of carbonate. 



Smith : The question arises as to whether there is a high-energy bond in this 

 intermediate ? 



