154 HARLYN HALVORSON 





 HOCH? Mg- ATP 



HCOH 



HCOH 2KG kinase 

 CH2OH CH^OPOI 



2-keto gluconate 2-keto-6-P04 



gluconate 



Fig. 12. 2-keto-6-phosphogluconate formation. 



for a rich supply of energy and biosynthetic intermediates through decar- 

 boxylation, carboxylation, clastic and aldehyde transfer reactions. 



The entire system for pyruvate oxidation was associated with a particu- 

 late fraction which was completely sedimented at 140,000 times gravity. 

 Rapid pyruvate oxidation occurred with the addition of DPN, ATP, cocar- 

 boxylase and MnClo. When the reaction mixture is sparked with oxalacetate 

 (OAA), an active oxidation of acetate, succinate, fumerate and OAA by 

 these particles was observed (Fig. 13). There was no detectable oxidation 

 of citrate, cis-aconitate or malate. Succinate oxidation was competitively in- 

 hibited by its analog, malonate, indicating the presence of succinic dehydro- 

 genase. On the other hand Hardwick and Foster (1953) observed oxidative 

 activity towards malate, succinate, a-ketoglutarate, and pyruvate in extracts 

 of vegetative cells but not of spores of Bacillus mycoides. Their failure to 

 detect oxidative activity in spore extracts was probably due to an insuffi- 

 cient endogenous supply of OAA to spark the reaction. 



The cofactor requirements and oxidative capacity of these particules sug- 

 gest that pyruvate is oxidized by the classical reactions of trioses known to 

 be present in vegetative cells of Bacillaceae. Pyruvate is probably oxida- 

 tively decarboxylated to an active acetate which is further metabolized via 

 either a dicarboxylic acid or tricarboxylic acid cycle. Although extracts do 

 not actively oxidize the tricarboxylic acids, we feel that the results are too 

 preliminary to favor a dicarboxylic acid cycle. Krask (this symposium) has 

 also shown the presence of an active CoA-kinase or acetokinase in extracts 

 of these spores. 



It also seems likely that pyruvate may be derived from alanine. The L- 

 alanine requirements for spore germination may be spared by pyruvate. 

 Recently, Falcone (1955) reported the production of H2O2 and pyruvate 

 from alanine by intact spores. We have also observed that intact spores of 



