Role of TPN in Control of Glycolysis 239 



Table II 



Influence of TPN and fresh mitochondria on glycolysis by a 

 BRAIN-S2 preparation 



Additions 



None 



TPN (1 iiM) 



Mitochondria (200 mg.-equiv.) 



TPN + mitochondria 



-IS, glucose 



(XM 



3-55 

 2-70 

 2-68 

 1-20 



-\-t^lactate 



(JLM 



302 



1-88 



1-37 



-005 



Composition of the medium as in Fig. 2. 



and it was evident even when the action of TPN alone was 

 sHght or absent (Fig. 2). 



TPN is slowly reduced by the brain supernatant, but it is 

 maintained in the oxidized form when mitochondria are 

 present (Fig. 5). These experiments seemed to indicate the 



ii 



(39) 



15 30 



TIME (MINUTES) 



30 



Fig. 5. Effect of mitochondria on the level of oxidation of tri- 

 phosphopyridine nucleotides incubated with brain supernatant. 

 The composition of the medium was as in Fig. 2 but 0-1 (jlm 

 cytochrome c was added. TPN was initially present in the experi- 

 ment of graph A, and TPN ( • ) or TPNH ( ■ ) in that of graph B. 

 The figures in parentheses correspond to the percentage inhibition 

 of glycolysis. The amount of mitochondria is given as mg.- 

 equiv. per flask and refers to the mitochondria obtained from the 

 indicated fresh weight of liver. 



