368 General Discussion 



problem of compartmentation in relation to glycogen synthesis in 

 yeast (this symposium, p. 256). I wonder whether the calculations 

 would still apply if the pathway of glycogen synthesis were different 

 from the pathway of glycogen breakdown? 



Lynen: The calculations would not apply only if the synthetic 

 pathway were much more efficient than the degradative one. How- 

 ever, it was shown that an active phosphorylase exists in yeast 

 cells. It does not matter whether this enzyme works in both pro- 

 cesses or only in degradation. In either case, if there were no com- 

 partmentation the high orthophosphate/glucose-1 -phosphate ratio 

 would cause glycogen to be degraded. 



Rocker: If glucose- 1 -phosphate is not the intermediate in glycogen 

 synthesis, but uridine diphosphate glucose is the true precursor, then 

 the equilibrium calculation with inorganic phosphate as a reactant 

 no longer applies. 



Lynen: You would have a cycle where glycogen is broken down 

 and synthesized again. 



Krehs: Before we disperse I would like to thank you for your 

 enthusiasm and keenness which made the task of the Chairman easy. 



I like to think that the symposium has been really worth while; 

 worth while for those of you who have come a long way to spend a 

 few days here, and worth while from the point of view of the Ciba 

 Foundation. The subject of the symposium is bound to grow in 

 importance in the coming years and I anticipate that the forth- 

 coming book which records our discussions will be a very valuable 

 one. As far as I am aware it will be the first book surveying a variety 

 of aspects of the non-hormonal regulation of cellular metabolism 

 and I hope it will prove to be a pioneer book. 



