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A comparison by magnetic circular dichroism of compound X and compound II of horseradish peroxidase
Author(s) -
Foote Nicholas,
Gadsby Paul M.A.,
Field Robert A.,
Greenwood Colin,
Thomson Andrew J.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80085-6
Subject(s) - chemistry , magnetic circular dichroism , horseradish peroxidase , porphyrin , circular dichroism , peroxidase , crystallography , spectroscopy , heme , photochemistry , enzyme , spectral line , organic chemistry , physics , astronomy , quantum mechanics
The chlorite product of horseradish peroxidase, compound X, is shown by magnetic circular dichroism (MCD) spectroscopy in the temperature range 1.6–50 K to have a very similar haem structure to compound II under the same conditions (pH 10.7). Both are concluded to contain the Fe(IV)=0 group. The MCD spectrum also detects an unusual species, absorbing at wavelengths between 600 and 750 nm, that has magnetic properties different from those of the ferryl haem group. It is suggested that this is a species at the same oxidation level as ferryl haem but with the porphyrin ring having suffered a one‐electron oxidation, i.e. [Fe(III) P .+ ].