A Plausible Prebiotic Origin of Glyoxylate: Nonenzymatic Transamination Reactions of Glycine with Formaldehyde

Glyoxylate has been postulated to be an important prebiotic building block. However, a plausible prebiotic availability of glyoxylate has not as yet been demonstrated. Herein we report the formation of glyoxylate by means of a transamination reaction between glycine and formaldehyde in water at 50 °C and 70 °C at pH 8 and 6, respectively. The reaction was followed by means of 13 C NMR and high-resolution mass spectrometry employing both unlabeled and 13 C-labeled reactants. Other products accompanying the transamination process include serine, sarcosine, N , N -dimethylglycine, and carbon dioxide/bicarbonate. The mechanisms for the formation of glyoxylate and accompanying products are discussed. 1 Introduction 2 Background 3 Results and Discussion 3.1 Reaction of 13 C-Labeled Glycine with Formaldehyde at pH 8 3.2 Reaction of 13 C-Labeled Glycine with Formaldehyde at pH 6 3.3 Serine-Promoted Decarboxylation of Glyoxylate 4 Conclusions