58 METABOLIC PATHWAYS IN MICROORGANISMS 



other positions in gluconate also agrees fairly well with 

 predictions. Nearly identical results were obtained in a 

 repeat experiment, not shown here, performed six weeks 

 later. 



It would appear from the above paragraph that fructose 

 exists in a general pool in this organism, and that it is 

 treated the same whether it is administered as substrate 

 or re-formed from the pentose cycle; it is apparently un- 

 necessary to make so extensive allowance for recycling as 

 Katz and Wood have done. Instead of a perfect equilibrium 

 existing among fructose- 1, 6-diP, glycolysis, and the pentose 

 cycle, there appears instead to be a steady state that, in 

 B. suhtilis at least, is shifted toward glycolysis and the TCA 

 cycle. These data support the assumption made by Dawes 

 and Holms (13) in Sarcina lutea, that re-formed fructose will 

 be degraded both by glycolysis and the pentose cycle. It 

 would appear likely that this condition may obtain in 

 animal systems as well; work is being planned in our 

 laboratories to test this assumption further. 



QUANTITATIVE EXPRESSION OF PATHWAY 

 PARTICIPATION 



The reader may now inquire whether so simple a cal- 

 culation as we have previously employed (11), can really 

 represent the complex events that take place in organisms, 



Gp = -^ ^ (footnote 3) (1) 



in spite of the seeming reinforcement given by the B. suh- 

 tilis experiment quoted. The fact is that the B. suhtilis 

 3 In the original report (11), G, and Gg were written as G^^' and G^'. 



