Vanadium catalysis in the nonenzymatic transamination of δ-aminolevulinic acid

Abstract

By nonenzymatic model reactions, the influence of vanadium (V0 2+, V03-) and other metal ions (Al3+, Fe2+, Fe3+, Zn2+, Ni2+, Cr3+) on the transamination of 4,5-dioxovaleric acid (DOVA) with L-alanine (ALA) to 6 δ-aminolevulinic acid (δ-ALA) and pyruvic acid (PA) with pyridoxal phosphate (PLP) is investigated. The examinations of the partial reactions show that VO2+, VO3- and Fe2+effectively enhance both conversions, while Ni2+ only promotes the conversion of DOVA to δ-ALA with pyridoxamine phosphate (PMP).Besides Cr3+, which inhibits the transaminations, all other metals tried slightly enhance both reactions. The coupled transamination DOVA/Ala to (δ-ALA/PA with PLPas a catalyst is performed at 40ºC, the extent of the reaction being judged by the amount of δ-ALA formed. Among all metal ions tested, VO2+ and VO3- were found to beM the mosteffective ones. Fe2+, Al3+ and Fe3+ also slightly enhance the reaction, but all other metals do not influence or inhibit the transamination. In presence of VO2+ or VO3- ions, the optimum pH of the reaction shifts from pH 4 to pH 7.4. The positive influence of vanadium on δ-ALA transaminationis discussed in connection with known structures of analogous Schiff base complexes with metal ions. © 1978, Walter de Gruyter. All rights reserved.