Significance of the equilibrium constant between serum ascorbate radical and ascorbic acids in man.

The spin concentration of ascorbate radical in human serum was examined and the existence of the stable equilibrium between the spin concentration of serum ascorbate radical and concentrations of ascorbic acids in healthy subjects was found. The value of the equilibrium constant was independent of age and sex. The administration of ascorbic acid caused the convergence of these values which were scattered within certain ranges in healthy volunteers. The values of the equilibrium constant increased in many patients with various diseases and returned to normal level with improvement of symptoms. These indicate that the equilibrium constant can be used as a clinical index to reflect metabolic state involving ascorbic acid as the radical scavenger.