FUNCTION 



cocarboxylase had only lo % of the activity of vitamin B^ in the 

 catatorulin test. Later, however, I. Banga, S. Ochoa and R. A. 

 Peters ^^ obtained evidence confirming Lohmann and Schuster's 

 hypothesis ; brain preparations that responded to aneurine apparently 

 synthesised cocarboxylase sufficiently rapidly to account for the 

 oxygen uptakes observed, whilst the inferior activity of cocarboxylase 

 in the catatorulin effect was due to its failure to reach the active centre, 

 as it was much less permeable than aneurine itself ; with finely minced 

 brain dispersions, cocarboxylase was very much more active. 



I. Banga, S. Ochoa and R. A. Peters *^ were further able to show 

 that the oxidative decarboxylation of pyruvate in brain, and prob- 

 ably in other animal tissues, was not so simple as reaction (i) above 

 indicates and required the presence of inorganic phosphate, C4-dicar- 

 boxylic acids {e.g. succinate, fumarate, malate, etc.), adenine nucleo- 

 tide, magnesium ions and probably cozymase. They did not, how- 

 ever, believe that the oxidation of pyruvate in brain involved the 

 Krebs' tricarboxylic acid cycle (see page 626). 



Aneurine Triphosphate 



When aneurine was phosphorylated with phosphoric acid that 

 had been desiccated at 350° C., the triphosphoric ester was formed. 

 This reduced or abolished the bradycardia produced by electrical 

 stimulation and increased the amplitude and regularised the rhythm 

 of heart-beats affected by fatigue or potassium chloride. Cocar- 

 boxylase had no such effect, whilst adenosine triphosphate only 

 affected the rhythm and not the bradycardia. Aneurine triphosphate 

 restored the carboxylase activity of washed yeast cells, but had only 

 about one-quarter the activity of cocarboxylase.^^ 



Dismutation of Pyruvic Acid 



A considerable body of evidence has now accumulated to suggest 

 that aneurine in the form of its pyrophosphate is concerned with the 

 dismutation reaction (3) rather than with reactions (i) or (2). G. M. 

 Hills 2^ reached this conclusion from a study of the oxygen uptake of 

 Staphylococcus aureus in presence and absence of aneurine, and his 

 results were confirmed by Kligler et al.,^^ who also found that, under 

 aerobic conditions, 5. aureus produced pyruvic and lactic acids from 

 glucose in the absence of aneurine. Under anaerobic conditions the 

 presence or absence of aneurine made no difference, the reaction being 

 purely glycolytic. When pyruvate was used instead of glucose the 

 absence of aneurine resulted in dismutation, producing equimolecular 

 amounts of lactic acid, acetic acid and carbon dioxide. This reaction 



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