Effect of Chelating Agents on Heavy Metal Catalysis

Abstract

IN a recent communication, Pirie and Van Heyningen¹ have reported “a case where a chelating agent accelerated the oxidation of a substance (glutathione), which it was intended to preserve in the reduced state”¹. The object of the chelating agent was “the removal of metals”, traces of which would presumably catalyse the oxidation. Since chelating agents are being generally used for this purpose, it seems worth while emphasizing that the metal chelate complexes formed are not necessarily without catalytic activity. Thus 1:10 phenanthroline, αα′di-pyridyl and αα′α″tripyridyl increase the iron-catalysed rate of decomposition of hydrogen peroxide by as much as one hundred-fold², and certain hæmoprotein complexes of iron are well known as catalysts in biological systems.