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Phillips W. Robbins and Fritz Lipmann 



glycogen synthesis but rather with glycogen utilization. Such a 

 proposition had also appeared to fit better with the results of 

 Sutherland and his collaborators on adrenaline effects (Sutherland, 

 1956). 



A very likely candidate for a system synthesizing glycogen more 

 effectively than phosphorylase*, was the recently discovered uridine 

 diphosphate glucose (UDPG)-linked glycogen synthesis of Leloir and 

 Cardini (1957). Here, the equilibrium is much more in favour of 

 synthesis than if glucose-1 -phosphate is the glucose feeder (Cori, 



40 



60 



20 



40 



W 



Time in minutes 



Fig. 5. Effect of phosphorylase kinase on incorporation of glucose- 

 6-phosphate into glycogen and glycogen maintenance. The incuba- 

 tions were carried out in 125-ml. Erlenmeyer flasks. i*C-glucose- 

 6-phosphate and phosphorylase kinase were added after 8 minutes of 

 incubation. Samples were withdrawn at the times indicated for in- 

 corporation measurements and chemical glycogen determination. 



Cori and Green, 1943; Cardini, Leloir and Chiriboga, 1955). In the 

 case of glycogen synthesis, the situation is even more favourable 

 than in sucrose synthesis (Cardini, Leloir and Chiriboga, 1955) since 

 the 1-4 glucosidic link in glycogen has a lower group potential than 

 the 1-2 glucosidic link in sucrose. In partial confirmation of such a 

 proposition, the synthesizing enzyme using the UDPG-glycogen 

 pathway has been found in muscle in high concentration, and 

 preliminary results also indicate the equilibrium to be almost com- 

 pletely on the side of glycogen synthesis^ (Robbins, Traut and Lip- 

 mann, 1959). 



* This paragraph includes data obtained during autumn 1958, in following 

 up the results reported at the symposium. 



t On a recent visit to the U.S.A., Dr. Leloir reported on studies on the 

 muscle enzyme catalysing UDPG-linked glycogen synthesis (Leloir et al., 1959). 



