[Abnormal metabolism of substances related to glycine and beta-alanine].

Glycine and serine are interconverted by serine hydroxymethyltransferase and hence share their metabolic pathways. In the rat the carbon skeleton of choline is derived from the alpha and beta carbons of serine through phosphatidylserine and is further converted to that of glycine through N-methylated molecules of glycine i.e. betaine, N-dimethylglycine, and sarcosine (N-methylglycine). Thus far, the production of a folate derivative of the active one carbon that is an essential material for purine nucleotides and thymidylate biosynthesis is the notable feature of this metabolic process. In the major degradative pathway for pyrimidine nucleotides, beta-alanine, one of omega-amino acids, is produced and further catabolized by beta-alanine: oxoglutarate transaminase which is suggested to be identical to that for gamma-aminobutyrate, another omega-amino acid. Disorders included in these metabolic pathways are succinctly reviewed.