ALKALI-CATALYZED ELIMINATION OF D-LACTIC ACID FROM MURAMIC ACID AND ITS DERIVATIVES AND DETERMINATION OF MURAMIC ACID

Treatment of muramic acid and of derivatives of muramic acid whose reducing group is free with alkali at 37° results in the elimination of the D-lactate moiety. A chromogen which reacts directly with p-di-methylaminobenzaldehyde to give a typical Morgan-Elson absorption spectrum is formed from reducing derivatives of N-acetylmuramic acid. The lactic acid derived from muramic acid in hydrolysates of several cell walls has been demonstrated to have the d configuration. Determination with D-lactate dehydrogenase of the D-lactate liberated by this procedure can be used to quantitate muramic acid in hydrolysates of cell wall materials. Elimination is more rapid when the lactic acid moiety is peptide substituted, and the chromogen isolated from such a material after incubation at 37° and pH 10.5 has been tentatively identified as Δ-2,3-N-acetylglucosamine (Δ-2,3-2-acetamido-2-deoxy-D-gluco-seen), the predicted result of nucleophilic attack on the C2 proton and consequent elimination of the C3 substituent. © 1968, American Chemical Society. All rights reserved.