VOL. 12 (1953) AMINO ACID INTERACTIONS IN STRICT ANAEROBES 



117 



amino acid oxidase. This is indicated by the relatively high resistance of alanine oxidation 

 to the presence of 8 /xg/ml mapharside (Table XIV) . Hydrogen uptake by the organisms 

 in the presence of proline at this concentration of mapharside is completely suppressed. 



TABLE XIV 



EFFECTS OF ORGANIC ARSENOXIDES ON THE ACTIVITIES OF RESTING CI. SpOVOgeneS 



Warburg manometer vessels contained i ml CI. spovogenes suspension (in 0.15 M KCl). Buffer 

 either 0.028 M NaHCOj or 0.02 M phosphate (pH 7.3) as indicated. L-Alanine = 0.02 M. L-ProHne 

 = 0.02 ill. Gas = 93% Ng + 7% COj or Air or Hydrogen as indicated. Total vol. 3.2 ml. Temp. 

 + 37°. Time 90'. 



The results indicate that the amino acid reductase of CI. sporogenes is a highly 

 vulnerable thiol system and appears to be the one most affected by the presence of 

 oxygen, hydrogen peroxide, or organic arsenoxides. 



The toxicity of organic arsenoxides to CI. sporogenes is reversible (see also Gordon 

 AND QuASTEL^*), the addition of glutathione (0.3%) to an organism, that has been 

 exposed for 30 minutes to phenylarsenoxide with a resultant drop of 84% in the rate of 

 alanine-proline interaction, causing almost complete (over 80%) recovery of activity. 



That the toxic action of the organic arsenoxide is due to the trivalent arsenic atom 

 is shown by the entire lack of toxic activity of the corresponding pentavalent arsenic 

 acids. 



DISCUSSION 



The results described in this preliminary survey of anaerobic amino acid interactions 

 in CI. sporogenes indicate that these interactions take place with diphosphopyridine 

 nucleotide (DPN) playing an intermediate role as hydrogen carrier. Ferricyanide together 

 with the amino acid hydrogen acceptors, and molecular hydrogen together with the 

 amino acid hydrogen donators, compete for the DPN carrier system. Pyruvate has been 



References p. 120. 



