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THE EFFECT OF FLUORIDE ON BINDING and PHOTODYNAMIC ACTION OF PHTHALOCYANINES WITH PROTEINS
Author(s) -
BenHur E.,
Dubbelman T. M. A. R.,
Steveninck J. Van
Publication year - 1991
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.1751-1097.1991.tb02078.x
Subject(s) - photobleaching , chemistry , fluoride , photochemistry , bovine serum albumin , phthalocyanine , photosensitizer , photodynamic therapy , tryptophan , metal , biophysics , fluorescence , inorganic chemistry , biochemistry , organic chemistry , amino acid , physics , quantum mechanics , biology
Fluoride inhibits chloroaluminum phthalocyanine tetrasulfonate (AIPcS)‐induced photo‐hemolysis when added to dye loaded cells prior to light exposure. The mechanism by which F˜ exerts this effect was studied by measuring the binding of phthalocyanine (Pc) to various proteins in the absence and presence of F − . Parallel measurements were made of the photodynamic action under these conditions. Fluoride reduced the binding to proteins of AIPcS and CoPcS. The binding of CuPcS, ZnPcS and H 2 PcS was not affected. When bound to bovine serum albumin and exposed to light, H 2 Pc, ZnPc and AIPcCI were bleached at a biphasic rate. Only the photobleaching of AIPcCI was affected by F − . The effect of F” was to inhibit the initial rapid phase without affecting the slower phase. In the presence of D 2 O only the second phase of photobleaching was enhanced, in the absence or presence of F − . No effect of F − was observed on tryptophan photooxidation or glyceraldehyde‐3‐phosphate dehydrogenase photoinactivation by AIPcS. Crosslinking of spectrin monomers photosensitized by AIPcS was inhibited by F − in parallel with the reduced binding of dye to the protein. It is concluded that F˜ exerts its effect by complexing with metal ligands of Pc. As a result, the dye may be released from the protein or the binding mode may be changed in such a way that effective photochemistry is prevented. Primary photophysical processes of Pc most probably are not affected by F −