VOL. 12 (1953) BIOCHIMICA ET BIOPHYSICA ACTA IO3 



AMINO ACID INTERACTIONS IN STRICT ANAEROBES 



{CL. SPOROGENES) 



by 



R. MAMELAK and J. H. QUASTEL 



Research Institute, Montreal General Hospital, Montreal (Canada) 



Following the demonstration by Quastel, Stephenson and Whetham^ and by 

 QuASTEL and Stephenson^ that anaerobic growth of facultative anaerobes is secured 

 by the presence in the nutrient medium of pairs of hydrogen donators and hydrogen 

 acceptors {e.g. lactate-fumarate, or glycerol-aspartate) whose interaction provides energy 

 for growth, and pyruvic acid for the synthetic requirements of the cell (Quastel^), 

 Stickland'1'5, and later Woods^^, showed that similar considerations, with respect to 

 energy formation, apply to strict anaerobes such as CI. sporogcnes. With these organisms, 

 however, the hydrogen donators and acceptors are amino acids. For example, L-alanine 

 and glycine form a pair of amino acids which interact in the presence of resting CL 

 sporogenes to form acetic acid, ammonia and carbon dioxide. 



Thus: CH3CHNH2COOH + 2CH2NH2-COOH + 2H2O = 3CH3COOH + 3NH3 + CO 3. 



Typical hydrogen donators are alanine, valine, leucine ; typical hydrogen acceptors are 

 glycine, proline, hydroxyproline. The interactions between pairs of these amino acids 

 have been referred to as Stickland reactions, and it has been considered that a-ketonic 

 acids are intermediates in these reactions. Neither Stickland, nor subsequent workers, 

 however, have been able to prove that in the alanine-glycine interaction (for example) 

 there is liberation of pyruvic acid. 



Stickland^ showed that pyruvate and glycine interact in the presence of resting 

 CI. sporogenes, the rate of pyruvate oxidation by glycine being greater than that of 

 alanine under similar experimental conditions. Thus the lack of appearance of pyruvate, 

 if it were formed, was held to be due to its high rate of reactivity with the amino acid 

 hydrogen acceptors. Kocholaty and Hoogerheide^' ^ using dyestuffs as hydrogen 

 acceptors, studied the dehydrogenases of CI. sporogenes concerned with the oxidation 

 of alanine, pyruvic acid, ethanol, and showed that their activities were affected by the 

 composition and pH of the culture medium, and by the age of the bacterial culture. 

 They further observed that hydrogen absorption will occur with resting CI. sporogenes in 

 presence of amino acid hydrogen acceptors e.g. hydroxyprohne, proline, glycine, 

 ornithine, arginine and tryptophan, and also in presence of such substances as acetyl- 

 methylcarbinol and diacetyl. They, and Woods^^, also made clear the fact that certain 

 amino acids e.g. ornithine, tryptophan, may act as both hydrogen donators and accep- 

 tors. Under such circumstances, an amino acid will break down anaerobically in presence 

 of resting CI. sporogenes to yield oxidation and reduction products e.g. two mols. tryp- 

 tophan yield one mol. indolepyruvic acid, one mol. indolepropionic acid and two mols, 

 ammonia. 

 References p. 120. 



