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THE PHOTODYNAMIC EFFECT OF ROSE BENGAL ON PROTEINS OF THE MITOCHONDRIAL INNER MEMBRANE
Author(s) -
Giulivi Cecilia,
Sarcansky Monica,
Rosenfeld Esteban,
Boveris Alberto
Publication year - 1990
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.1751-1097.1990.tb08676.x
Subject(s) - rose bengal , tbars , singlet oxygen , submitochondrial particle , chemistry , histidine , polyunsaturated fatty acid , photochemistry , biochemistry , hypochlorous acid , reactive oxygen species , myoglobin , lipid peroxidation , oxygen , fatty acid , mitochondrion , amino acid , organic chemistry , oxidative stress
— Photodynamic action promoted by Rose Bengal was evaluated in solutions of unsaturated fatty acids or histidine, and on beef heart submitochondrial particles. Rose Bengal‐promoted photo‐oxidation of histidine was mainly due to the opening up of the imidazole ring by singlet oxygen. Photosensitization of polyunsaturated fatty acids (PUFA) resulted in oxygen consumption and thiobar‐bituric acid‐reactive substances (TBARS) formation, the extent of which was linearly related to the increasing degree of unsaturation. Photosensitization of submitochondrial particles caused oxygen consumption and TBARS production. These processes involved two different reaction components: during the first, most of the mitochondrial proteins were inactivated, the most sensitive being succinate dehydrogenase and cytochrome c. The values for the rate ratios of [TBARS] formation/[0 2 ] consumption for the first and second phase were 0.36 and 1.32%, respectively, pointing to a larger contribution of lipid peroxidation during the second phase. The calculation of the rate constants for reaction of singlet oxygen with mitochondrial proteins suggests that singlet oxygen is more reactive towards proteins than to PUFA. The biological role of this selectivity is discussed in terms of the mitochondria as one of the first targets for photosensitized reactions.