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IRON‐SULFUR CENTERS AS ENDOGENOUS BLUE LIGHT SENSITIZERS IN CELLS: A STUDY WITH AN ARTIFICIAL NON‐HEME IRON PROTEIN
Author(s) -
Kim Chang Sook,
Jung Jin
Publication year - 1992
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.1751-1097.1992.tb09603.x
Subject(s) - chemistry , singlet oxygen , photochemistry , ferredoxin , rose bengal , lipid peroxidation , liposome , histidine , chromophore , azide , photosensitizer , heme , oxygen , biochemistry , oxidative stress , organic chemistry , enzyme
— The possible involvement of Fe‐S clusters in photodynamic reactions as endogenous sensitizing chromophores in cells has been investigated, by using an artificial non‐heme iron protein (ANHIP) derived from bovine serum albumin and ferredoxins isolated from spinach and a red marine algae. Ferredoxins and ANHIP, when exposed to visible light, generate singlet oxygen, as measured by the imidazole plus RNO method. Irradiation with intense blue light of the ANHIP‐entrapped liposomes caused severe membrane‐damage such as liposomal lysis and lipid peroxidation. In the presence of ANHIP, isocitrate dehydrogenase and fructose‐l, 6‐diphosphatase were photoinactivated by blue light. However, all of these photosensitized reactions were significantly suppressed by a singlet oxygen ( 1 O 2 ) quencher, azide, but enhanced by a medium containing deuterium oxide. Further, the Fe‐S proteins with the prosthetic groups destroyed did not initiate the blue light‐induced reactions. In addition, the action spectrum for 1 O 2 generation from ANHIP was very similar to the visible absorption spectrum of Fe‐S centers. The results obtained in this investigation appear consistent with the suggestion that Fe‐S centers are involved in photosensitization in cells via a singlet oxygen mechanism.