38 



Philip Siekevitz 

 Table VI 



Specific activities of glutamic acid and glutamine 



AFTER injection INTO MICE 



Sp. act. of isolated comp. 



Data taken from Lajtha, Berl and Waelsch (1959). 



can be other explanations, of course, but there is no evidence 

 as yet which goes against the conclusions of these authors. 

 It would, therefore, be intriguing and fairly easy to see if the 

 glucose-6-phosphate to glucose system behaves in the same 

 manner, and this is being done at present. 



The rest of the scheme in Fig. 13 shows the possibility that 

 the whole chain of events in the initial stages of glucose 

 metabolism might take place at the surface of the ER mem- 

 branes. For the sake of simplicity, several enzymes, including 

 amylo-1 : 6-glucosidase, have been omitted. It has been 

 suggested quite a few times in the past that the purpose of the 

 DPNH- and TPNH-cytochrome c reductases in the microsome 

 might be to act as coenzymes for glycolysis and in the initial 



