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SINGLET OXYGEN GENERATION BY FUROCOUMARINS: EFFECT OF DNA AND LIPOSOMES
Author(s) -
Blan Quaseem A.,
Grossweiner Leonard I.
Publication year - 1987
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.1751-1097.1987.tb05361.x
Subject(s) - singlet oxygen , furocoumarins , liposome , psoralen , chemistry , lipid peroxidation , phototoxicity , photochemistry , crocin , phosphatidylcholine , quantum yield , dna , membrane , oxygen , fluorescence , biochemistry , antioxidant , organic chemistry , in vitro , phospholipid , physics , quantum mechanics
The quantum yield of singlet oxygen generation by aqueous furocoumarins was measured at 365 nm using the photosensitized inactivation of subtilisin Carlsberg as the probe with the following results: psoralen (0.18), 5‐methoxypsoralen (0.013), and 8‐methoxypsoralen (0.035). Singlet oxygen formation was significant for dark complexes of 8‐MOP with calf thymus DNA and the covalent DNA photoadducts. Incorporation of 8‐MOP in sonicated egg phosphatidylcholine liposomes did not inhibit photosensitization of subtilisin Carlsberg and also led to lipid peroxidation, with positive tests for the involvement of singlet oxygen. Peroxidation of the liposomes was inhibited by the presence of α‐tocopherol and promoted by the presence of cholesterol in the membranes.