I 50 



HILLEL S. LEVINSON 



12 3 4 



HOMOGENATE INCUBATED (HOURS) 



Fig. 9. Influence of time of incubation of homogenates on stimulation of 

 oxygen consumption by extracts derived from them. Extracts prepared by 

 centrifuging homogenates which had been incubated at 37 °C for various 

 periods of time. Reaction systems for oxygen consumption measurements 

 contained ammonium and potassium acetates ( pH 6.8. 0.05M each I ; glucose 

 (0.025M); intact spores (3.0 mg I ; and extract equivalent to that derived 

 from 2.5 mg spores. 



3. Products of this hydrolysis of spore protein — L-alanine. for example 

 — are capable of marked stimulation of spore germination. 



4. Manganese stimulates both proteolysis and spore germination. 



More recently, and none of this is published, we have been working with 

 ihe enzyme pyrophosphatase in extracts of the spores of B. megateriiim. As 

 we test it, the enzyme catalyses the hvdrolysis of sodium pvrophosphate to 

 give orthophosphate: 



Na4P,0T + H,0^ 2 Na.HFOi 

 There is not really much that I can sa) about the reaction. Its main interest 

 to me lies in the observation (Fig. 10 1 that the activit\ of the enzyme is 

 dependent on manganese. Without the addition of manganous ion we find 

 either no activity or an extren:ely low activity, but with oxlO^M manganese 

 we find nearly maximal activity. Cobalt and zinc also show a small amount 

 of activation. The pH optimum I Fig. 11 ) for this manganese-activated pyro- 



