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



10: 



accomplish this reduction are those that normally act as hydrogen donators in the 

 "Stickland" reaction. Amino acids that do not normally act as hydrogen donators have 

 little or no activity with ferricyanide. 



TABLE II 



AMINO ACID-FERRICYANIDE INTERACTIONS IN PRESENCE OF CI. SpOrOgenCS 



Amino acids placed in Warburg manometer vessels in 0.028 M NaHCOj in presence of 93% Ng + 

 7% COg. Final concn. amino acids 0.02 M (as L-form) (Temp. 37°, Time 45). i ml fresh CI. sporogenes 

 suspension in 0.15 M KCl. 0.2 ml 8% K3 Fe (CN)g placed in side tube. 



Substrate 



Amino acid 

 IXM COi i_iM NH, 



Amino acid + ferricyanide 

 flM CO, fxM NH3 



Nil 



DL-Alanine 



DL-Methionino 



L-Leucine 



L-Ornithine 



L-Glutamate 



DL-Alanine 



DL-Alanine -f Glycine 



During alanine-ferricyanide interaction in presence of CI. sporogenes, ammonia is 

 formed, but at a rate markedly less than that occurring in the alanine-glycine inter- 

 action. This is due largely to the fact that reduction of glycine gives rise to ammonia. 

 On mixing ferricyanide with alanine and glycine, it is found that the rate of ammonia 

 formation is that obtained in the alanine-ferricyanide reaction (see Table II). Thus 

 glycine reduction is suppressed and it is evident, as has been confirmed by chromato- 

 graphic evidence, that the utilisation of glycine is inhibited by the presence of ferri- 

 cyanide. Ferricyanide, therefore, competes as a hydrogen acceptor with glycine and 

 presumably with other amino acid hydrogen acceptors in CI. sporogenes. 



Hydrogen as a competitive hydrogen donator with CI. sporogenes 



As is well known', hydrogen is absorbed by resting CI. sporogenes in presence of a 

 variety of hydrogen acceptors. Ammonia is liberated when hydrogen is absorbed by 

 the organism in presence of glycine but not in presence of proline, which is reduced to 

 <5-aminovaleric acid*. Typical results showing rates of hydrogen uptake and ammonia 

 formation are given in Table III. 



TABLE III 



INFLUENCE OF AMINO ACIDS ON HYDROGEN ABSORPTION BY CI. SpOVOgeneS 



Amino acids (0.02 M) added to phosphate buffer (0.02 M; pH 7.4) in Warburg manometer 

 vessels in presence of i ml suspension freshly prepared CI. sporogenes in 0.15 M KCI. Final vol. 3.2 

 ml. Gas = hydrogen. Temp. 37^. Time 125' Proline placed in side tube and tipped at commence- 

 ment of expt. 



Amino acid 



/xM Hi uptake 



flM NH3 formed 



Nil 



Glycine 



L-Prohne 



L-Alanine + Glycine 



L-Alanine + L-Proline 



In presence of 0.028 M NaHCOg and 93% Ng + 



L-Alanine + Glycine 



L-Alanine + L-Proline 



3-7 

 II-3 



14.2 

 4.0 

 1.8 



7°/ 



/ /o 



CO., 



1.2 

 18.0 



3-5 

 390 

 41.0 



38.2 

 39-0 



References p. 120. 



