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PHOTOOXIDATION OF CHLOROPHYLL AND PHEOPHYTIN. QUENCHING OF SINGLET OXYGEN AND INFLUENCE OF THE MICELLAR STRUCTURE
Author(s) -
Chauvet JeanPaul,
Villain Françoise,
Viovy Roger
Publication year - 1981
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.1751-1097.1981.tb09042.x
Subject(s) - chemistry , pheophytin , photochemistry , singlet oxygen , oxidizing agent , radical , quenching (fluorescence) , oxygen , chlorophyll , reagent , yield (engineering) , organic chemistry , fluorescence , photosystem ii , photosynthesis , materials science , biochemistry , physics , quantum mechanics , metallurgy
— When chlorophyll(Chl) and pheophytin(Phn) are irradiated in Triton X‐100 water binary solvents, singlet oxygen is formed in the medium in a higher yield for Phn than for Chi. Chlorophyll shows an irreversible photooxidation reaction and a chemical oxidation reaction when 1,3‐diphenyliso‐benzofuran (DPBF) is added to the solution. During the chemical oxidation, Chi is destroyed by an oxidizing agent that is a reaction product of the endoperoxide formed in the medium by the addition of singlet oxygen to DPBF. This reaction depends on the structure of the medium and has some characteristics of an oxidation by hydroxyl radicals. The highest yield is obtained with the micellar structure. Chlorophyll and Phn are readily oxidized by hydroxyl radicals generated using the Fenton reagent. This suggests that in the presence of Triton X‐100, the Mg 2+ ion of a Chi molecule plays a key role in the irreversible oxidation of the pigment.