430 BIRGIT VENNESLAND 



Vennesland : As Warburg writes it I should say there is a high-energy bond 

 and you would presumably get an energy boost for the liberation of oxygen from 

 this high-energy bond. 



Lynen : We have recently been interested in the interaction of COo with biotin 

 and I should like to ask whether you have tried the effect of avidin on this process ? 



Vennesland : No, we haven't tried it. 



Dische: In your experiments the rate of the Hill reaction declined with time. 

 Is it not possible that the effect of CO^ is simply to slow down the decline of the 

 reaction ? 



Vennesland : We could reactivate the inhibited reaction with CO.,. 



Lowenstein : If you want to leave phosphate out of the scheme entirely, then 

 it is easier to envisage oxygen being split out of performic acid than out of car- 

 bonic acid. 



Vennesland: I don't think the evidence that I have available makes it possible 

 to choose between two such alternatives. 



Lowenstein: It is hard to visualize oxygen being split out of carbonate as 

 oxygen (O2). 



Vennesland : I think Warburg envisages the reaction as occurring on the 

 chlorophyll, with the COo bound in some way. The bound CO^ could have quite 

 different chemical properties from free COo. 



