Magnetic susceptibility, heme protein complexes

Mott transition, 25 170-172 paramagnetic states, 25 148-161, 165-169 continuum model, 25 159-161 ESR. studies, 25 152-157 multistate model, 25 159 optical spectra, 25 157-159 and solvated electrons, 25 138-142 quantitative theory, 25 138-142 spin-equilibria complexes, 32 2-3, see also specific complex four-coordinated d type, 32 2 implications, 32 43-44 excited states, 32 47-48 porphyrins and heme proteins, 32 48-49 electron transfer, 32 45-46 race-mization and isomerization, 32 44—45 substitution, 32 46 in solid state, 32 36-39 lifetime limits, 32 37-38 measured rates, 32 38-39 in solution, 32 22-36 static properties electronic spectra, 32 12-13 geometric structure, 32 6-11 magnetic susceptibility, 32 4-6 vibrational spectra, 32 13 summary and interpretation... 

The reversible one-electron oxidation-reduction of various heme proteins together with their similarity in spectra and magnetic susceptibilities establishes that the heme proteins normally occur in the ferrous and ferric states. However there is evidence that other states of oxidation may occur. For example, horse radish peroxidase is normally in the ferric state. Addition of HgOa forms intermediate (I), a green complex [Fe+++-peroxidase-HgOa] that has an absorption band at 657 m/i. Addition of one electron yields a red complex (II), which on addition of a second electron results in the appearance of the original ferric peroxidase. Is the red complex (II) [Fe+++-peroxidase-HO], or (Fe++++-peroxidase), or [Fe+++-peroxidase-... 

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