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



Effects of pyruvate addition on amino acid interaction in presence of CI. sporogenes extract 



In view of the conclusion that pyruvate must be produced in an alanine-proline 

 interaction at a concentration sufficient to saturate pyruvic oxidase, even when pyruvate 

 is being diverted to lactate by the presence of lactic dehydrogenase, it seems surprising 

 that pyruvate does not accumulate normally in sufficient amounts to be isolated or even 

 detected. The reason for this is that accumulation of pyruvate retards the process of 

 alanine oxidation by DPN, either by substrate competition or through reversibility of 

 action. Typical results showing this phenomenon are given in Table VIII. It will be seen 

 that the rate of evolution of carbon dioxide is unaffected by a concentration of pyruvate 

 that halves the rate of ammonia formation. It is evident that the pyruvic oxidase 

 system is saturated at low concentrations of pyruvate, increase of which diminishes the 

 rate of alanine oxidation. Clearly, a process that diverts pyruvate {e.g. to lactate) may 

 prevent retardation of alanine oxidation and allow the amino acid interaction to proceed 

 at an undiminished rate. 



TABLE VIII 



EFFECT OF SODIUM PYRUVATE ON AMINO ACID INTERACTION IN EXTRACTS OF CI. SpOrOgCneS 



Warburg manometer vessel contained i ml cell free CI. sporogenes extract (in i % sodium 

 thioglycollate and 0.002% phosphate) 0.028 NaHCOj. Gas = 93 % Nj + 7 % COg. Amino acids = 

 0.02 M L-form, DPN = 3 mg/vessel. Total vol. 3.2 ml. Time 80'. Temp. 37°. 



Contents of vessel fiM CO^ jxM NH3 



No substrate 3.4 7.0 



Alanine + Proline 32.0 40.5 



Alanine + Proline + o.oi M Pyruvate 32.0 21.2 



Alanine + Proline -|- 0.005 -^ Pyruvate 32.5 33.4 



Alanine + Proline + 0.0025 ^ Pjnruvate 32.5 39.5 



Acetylation of sulfanilamide due to amino acid interaction in presence of CI. sporogenes 



The interaction of alanine and proline by an extract of CI. sporogenes will bring 

 about a disappearance of sulfanilamide in presence of an extract of pigeon liver powder, 

 presumably by acetylation as acetic acid is a known product of the interaction. 



Results given in Table IX show that a mixture of bacterial extract and pigeon liver 

 extract, without added amino acids, accomplishes an acetylation of sulfanilamide, but 

 that the rate of acetylation is markedly enhanced by the addition of a mixture of alanine 

 and proline. Pyruvate may be substituted for alanine with a like effect on sulfanilamide 

 acetylation. The presence of arsenite, which greatly inhibits amino acid interaction, also 

 inhibits the increased sulfanilamide acetylation due to the amino acid interaction. 



The addition of adenosine triphosphate has but little effect on the speed of acetyl- 

 ation of sulfanilamide by an amino acid interaction in presence of pigeon liver extract. 

 This result, however, has little meaning, as extracts of CI. sporogenes have a powerful 

 ATP-ase activity, a concentration of 0.008 M ATP being completely decomposed in less 

 than 20 minutes by an extract, under the experimental conditions quoted in Table IX. 



In view of the high ATP-ase of CI. sporogenes extracts it seems unlikely that the 

 acetylation of sulfanilamide in such extracts is being mediated through the synthesis 

 of ATP produced by amino acid interactions. It is more likely that the following reactions 

 take place: 



References p. 120. 



