OXIDATIVE ENZYMES OF lUCTEHlAl. SPOKE EXTKACTS 



149 



glucose 



I ATP 



glucose-6-POir 



■2H 



-* gluconate 



ATP 



-2H 



-2H 



2-keto gluconate 

 Iatp 



6'-P04-gluconate 2 -keto-6- PO4- 



\ gluconate 



^-2H 



-CO2 



ribose-5-P04 



/ 



sedoheptulose- 



2-keto-3-clesoxy- 

 6-PO^- gluconate 



fructose -6- PO. 



glyceraldehyde-*zz 

 3-PO. DPN 



ijpyruvate 



ATP 



fructose-l,6-di-P04 



Fig. 6. Pathways of pyruvate formation frt)iii glucose. 



to reveal the presence of phosphate esters. These extracts were also devoid 

 of hexokinase and phosphohexokinase activities (Church, 1955). In addi- 

 tion there was no detectable phosphorylation of fructose, arabinose, ribose 

 or G-6-P. The absence of a functional aldolase and triose-phosphate-dehydro- 

 genase followed from the failure to detect TPN or DPN reduction in the 

 presence of F-1, 6-di P. or F-6-P. 



Oxidative pathivay 



To further define the oxidative pathways operative in spores, a charac- 

 terization of the end products of glucose oxidation by spore extracts was 

 undertaken. A chromatographic analysis of the deproteinized reaction mix- 

 ture is shown in Fig. 7. The primary end products are gluconate with 

 traces of 2KG, 2K6PG and pyruvate. A further identification of 2KG was 

 obtained by eluting it from the chromatogram and condensing it with 0- 

 phenylene diamine. The spectrum of 2-ketogluconate-O-phenylenediamine 

 complex was identical to that obtained with a synthetic sample (Fanning 

 and Cohen, 1951). 



The first recognized product of glucose oxidation by these extracts was 

 gluconate. This could arise either by direct oxidation of glucose or by the 

 action of hexokinase, G-6-P dehydrogenase, and a dephosphorylation of 6- 

 P-G. The latter route could not be the explanation because of the absence 

 of both hexokinase and a system of dephosphorylating 6-P-G. Furthermore, 



