DORMANCY OF BACTERIAL ENDOSPORE 79 



spores and extracts of activated spores. A summary of some of the 

 individual reactions demonstrated in extracts by enzyme purifi- 

 cation and end product analysis are shown in Fig. 3, ref.-^. The 

 compounds in large letters are primary germinating agents and 

 those underlined are less effective germinating agents. Glucose 

 is initially oxidized to gluconate by a soluble DPN-linked 

 glucose dehydrogenase. Spores are devoid of hexokinase, 

 phosphoglucomutase, phosphohexokinase and aldolase and 

 subsequently lack a functional glycolytic system. Gluconate is 

 converted to 2KG by a TPN-linked system which is in turn 

 phosphorylated to 2K6PG by an ATP-requiring 2KG kinase. 

 2K6PG is reduced in part to 6PG by a DPNH requiring 2K6PG 

 reductase and in part to pyruvate by an as yet unidentified 

 pathway. Spore extracts contain a complete functional hexose 

 monophosphate shunt which leads to triose formation which is 

 in turn converted to pyruvate. Pyruvate is oxidatively decarbox- 

 ylated to acetate which is then oxidized to CO2 by a particulate 

 tricarboxylic acid cycle. 



The observation that inosine serves as a more effective 

 germinating agent than adenosine led to the discovery of an 

 adenosine deaminase which converts adenosine to inosine and 

 a heat-stable hydrolytic nucleoside ribosidase which cleaves 

 inosine to the free base and ribose-^' ^9. Krask and Fulk^o have 

 demonstrated in these extracts the presence of a Mg-+ activated 

 ribokinase which in the presence of ATP converts ribose to 

 R5P. Alternatively they found that some of the ribose is con- 

 verted to RIP from adenosine by nucleoside phosphorylase 

 which is converted to R5P by an active phosphoribomutase. 



The cardinal role of L-alanine in the germination of aerobic 

 spores has led to a further search for its metabolism. The 

 observation that L-alanine is consumed during germination-^' 

 26, 31, 32 led to the demonstration that isotopically labeled 

 L-alanine is converted to pyruvate and NHs^^. The relevant 

 enzyme, alanine dehydrogenase, has since been isolated and 

 characterized^^. 



References p. 94 



