The deamination and synthesis of 1-aspartic acid in the presence of bacteria

Abstract

IT was shown by Quastel and Woolf [1926] that when I-aspartic acid is incu- bated anaerobically with resting B. coli communis at 370 and PH 7-4, complete deamination occurs, fumaric acid appearing in the early stages of the reaction, to be replaced later by" succinic acid. If fumaric acid and ammonium chloride are incubated under the same conditions, there is first an ammonia uptake and a synthesis of l-aspartic acid, followed by the reappearance of all the ammonia, at which point nothing but succinic acid can be found in the medium. In the presence, however, of certain inhibiting substances, such as 2 or 4 % propyl alcohol, M/20 or M/10 sodium nitrite,'or'toluene, the production of succinic acid is completely inhibited. Under these circumstances, only fumaric acid is formed from aspartic acid; and aspartic acid from fumaric acid and ammonia, the reaction being a true chemical equilibrium for which equilibrium curves were obtained and the constant calculated. Resting B. coli thus appears to be able to effect two distinct chemical reactions, one reversible COOH. CH2. CH(NH,). COOH = COOH. CH: CH. COOH +NH9 which persists in the presence of inhibitors which completely abolish the other, irreversible reaction COOH. COH. CH(NH) . COOH+2H -> COOH. CH2. C12. COOH+NH,.