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ON THE MECHANISMS OF PHOTOLYSIS OF COMPOUNDS I AND II OF HORSERADISH PEROXIDASE AT 77 K*
Author(s) -
Nadezhdin A. D.,
Dunford H. B.
Publication year - 1979
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1979.tb07789.x
Subject(s) - photodissociation , chemistry , horseradish peroxidase , photochemistry , wavelength , irradiation , electron paramagnetic resonance , peroxidase , organic chemistry , materials science , nuclear magnetic resonance , enzyme , physics , optoelectronics , nuclear physics
Abstract—When Compounds I and II of horseradish peroxidase in glycerol/water glasses at 77 K were irradiated with the light of a mercury lamp, some changes in optical spectra as well as the development of strong EPR signals of a free‐radical type were detected. In case of photolysis of Compound I the light of wavelengths around 400 nm was the most effective, while only short wavelength (≥ 280 nm) light affected Compound II. The results of experiments with thawing and freezing the product of photolysis of Compound I (called Intermediate Y) provide further evidence for the suggestion that the ferric state of the heme iron is generated in the course of the photolysis. The quantum yields of the photolysis of Compound I at different wavelengths of irradiating light were obtained and mechanisms of the photolysis of Compounds I and II are proposed.