THE METABOLISM OF 2-CARBON COMPOUNDS RELATED TO GLYCINE

Abstract

In a continuation of the search for intermediates involved in the condensation of the a-carbon atoms of 2 glycine molecules (l), investigations were carried out with ethanolamine-l-C13,2-C14 (C13H20H-C14H2NH2).It was considered possible that the serine synthesized from administered glycine-2-Cl4 is, at first, labeled only in the a-carbon atom, the P-carbon atom being derived from unlabeled, endogenous sources of "formate."If the ethanolamine formed from this serine (2) were capable of yielding a labeled lcarbon fragment, cr,/3-labeled serine would be produced.The results described below failed to support such a reaction scheme.It was shown, however, that a major reaction in the metabolism of ethanolamine is deamination, oxidation, and reamination to glycine.With aspartic acid labeled with N15 as a source of labeled nitrogen, indirect evidence was also obtained for the conversion of glycolaldehyde to glycine.EXPERIMENTAL Preparation of Ethanolamine-I-C 13, D-d-C'4 (C13DzOH-C14H2NHz)-A mixture of 76 mg. of C14H&OOKa2 and 556 mg. of CH&?300Na was converted to acetyl bromide (3), and the product was used to synthesize