On the possible involvement of ascorbic acid and copper proteins in leukemia. III. ESR investigations on the interaction between ascorbic acid and some transition metal ions.

The interaction between lyophilized samples of ascorbic acid and Cu2+, Fe3+ or Mn2+ has been investigated by means of ESR spectroscopy. All of the three transition metal ions form complexes with vitamin C, but only in the case of Cu2+ and Fe3+ the interaction results in a reduction of the metal ions. Cu2+ and ascorbic acid seem to form 2 : 1 complexes with an equilibrium constant of about K = 1 X 10(7) mol-1. None of these metal ion complexes exhibits, however, the ESR spectrum obtained with leukemic blood.