title: The influence of amino acid ligands and vitamin C on the reduction potential of Fe (III): polarographic and electron spin resonance investigations.
abstract: The pH dependence of Fe(III)-amino acid complexes has been studied polarographically and by means of ESR spectroscopy. It could be shown that, at least, two complexes exist: one with a low molecular weight, ESR detectable at acid pH, and one with a high molecular weight at alkaline pH, ESR non detectable. The half wave potential of Fe(III) is lowered by amino acid ligands. The redox interaction of the Fe(III)-amino acid complexes with vitamin C results in a decrease of the ascorbyl radical concentration. Ascorbic acid also forms a complex with Fe(III) as indicated by a polarographic half wave potential near -0.55 V vs. S.C.E. at pH 7.
mesh_terms: D000409:Alanine; D000596:Amino Acids; D001205:Ascorbic Acid / Q000494:pharmacology*; D001224:Aspartic Acid; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds; D006639:Histidine; D006863:Hydrogen-Ion Concentration; D007501:Iron; D008024:Ligands; D009566:Nitrates; D010084:Oxidation-Reduction; D011048:Polarography
chemical_list: D000596:Amino Acids; D005290:Ferric Compounds; D008024:Ligands; D009566:Nitrates; D001224:Aspartic Acid; D006639:Histidine; D007501:Iron; C025302:ferric nitrate; D000409:Alanine; D001205:Ascorbic Acid