Enhanced axial symmetry at the Fe(3+)-heme center of peroxidase by ascorbate: a basis for the ascorbate-dependent peroxidase action.

In the absence of its substrate hydrogen peroxide, peroxidase exhibits perturbations in its Fe(3+)-heme center, when incubated with ascorbic acid. The electron paramagnetic pattern sprang towards a higher g-value side, denoting a sharpening of the rhombic axial symmetry around the heme-center. The interpretation is that the ascorbate dependent peroxidase action starts with the formation of an Fe(3+)-ascorbate charge transfer complex intermediate.