Amino acid interactions in strict anaerobes (Cl. Sporogenes)

Abstract

1. 1. Amino acid hydrogen donators compete with each other, and amino acid hydrogen acceptors also compete with each other, in anaerobic amino acid interactions in Cl. sporogenes. 2. 2. The competition of these substances is due to the fact that diphosphopyridine nucleotide acts as a common hydrogen carrier between the amino acid hydrogen donators and the amino acid hydrogen acceptors. 3. 3. Molecular hydrogen absorption by amino acid hydrogen acceptors is greatly suppressed by the presence of amino acid hydrogen donators in Cl. sporogenes. 4. 4. Ferricyanide acts as a hydrogen acceptor, competing with amino acid hydrogen acceptors, in Cl. sporogenes. 5. 5. Pyruvate is established as an intermediate in anaerobic alanine-proline interaction in Cl. sporogenes, by its diversion to lactate in presence of lactic dehydrogenase of animal tissues. 6. 6. Anaerobic amino acid interactions, as well as pyruvate-amino acid interaction, give rise to sulfanilamide acetylation in extracts of Cl. sporogenes, when an extract of pigeon liver is added. 7. 7. Aerobic alanine oxidation by Cl. sporogenes is greatly accelerated by the presence of pyruvate or α-ketoglutarate, which acts in this way by non-enzymic interaction with hydrogen peroxide (formed during alanine oxidation). 8. 8. Exposure of Cl. sporogenes to air, oxygen or hydrogen peroxide, exert highly toxic effects on amino acid oxidations or anaerobic interactions. These may be prevented by the presence of pyruvate or of thiol compounds. 9. 9. The toxic effects of air or oxygen or dilute hydrogen peroxide on the enzymatic mechanisms of Cl. sporogenes may be reversed by subsequent additions of thiol compounds. It is suggested that the amino acid activating enzymes are thiol systems, which are converted to the inert-S-S-form by oxygen or dilute hydrogen peroxide. This inert form may be converted to the active -SH form by treatment with thiol compounds. 10. 10. The amino acid activating enzymes, particularly the amino acid reductases, are highly sensitive to organic arsenoxides which exert large inhibitory effects on amino acid interactions in Cl. sporogenes.