Reaction of glycine with glyoxylate: Competing transaminations, aldol reactions, and decarboxylations

Abstract

The reactions of glycine, a simple amino acid, with glyoxylate, a simple α-oxocarboxylate, were investigated in water as a function of time, pH, and temperature and followed using a combination of quantitative 13C nuclear magnetic resonance and high-resolution mass spectrometry. Three sets of experiments are reported: (1) reaction of 13C-labeled glycine with unlabeled glyoxylate, (2) reaction of unlabeled glycine with 13C-labeled glyoxylate, and (3) the reaction of 13C-labeled glycine with 13C-labeled glyoxylate. Competing transaminations, aldol reactions, and decarboxylations were observed; the mechanistic description for each of these processes is presented. 3-Hydroxy-2-aminosuccinate, a product of reaction between glycine and glyoxylate, was shown to promote both the decarboxylation of glyoxylate and transamination of glyoxylate to glycine. These observations may have implications for the mechanism of attenuation of ethylene glycol toxicity.