CHEMICAL SYNTHESIS OF 4,5-DIOXOVALERIC ACID AND ITS NON-ENZYMATIC TRANSAMINATION TO 5-AMINOLEVULINIC ACID

4,5-Dioxovaleric acid (DOVA) was synthesized from 5-bromolevulinic acid via formation of the pyridinium bromide of 5-bromolevulinic acid, followed by nitrone formation with p-nitrosodimethylaniline, and hydrolysis of the nitrone to yield DOVA. Partial purification of DOVA was obtained by passage of the reaction mixture through a cation exchange column. DOVA was identified by paper electrophoresis and by a specific fluorometric assay. DOVA was nonenzymatically transaminated to 5-aminolevulinic acid (ALA) with glycine serving as the amino donor. Other compounds tested were less effective amino donors. Glyoxylic acid was identified as a reaction product by paper electrophoresis and a specific calorimetric test. ALA was identified by paper electrophoresis, paper chromatography of a pyrrole derivative, reaction with Ehrlich reagent, and by its enzymatic conversion by a barley extract to porphobilinogen and uroporphyrin. The nonenzymatic transamination was inhibited by Tris and was stimulated by high pH. The existence of this nonenzymatic activity is discussed in relation to previous reports of dova transaminase activity in cell extracts. © 1979.