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PHOTOCHEMICAL PROPERTIES OF PORPHYRIN c : AN AGENT FOR USE IN TUMOR PHOTOTHERAPY
Author(s) -
Ghiggino Kenneth P.,
Bennett Louise E.,
Henderson Robert W.
Publication year - 1988
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.1751-1097.1988.tb02696.x
Subject(s) - porphyrin , hematoporphyrin , photochemistry , fluorescence , chemistry , chromophore , quantum yield , aqueous solution , monomer , singlet oxygen , absorption (acoustics) , photosensitivity , phototoxicity , micelle , oxygen , organic chemistry , photodynamic therapy , materials science , polymer , biochemistry , physics , optoelectronics , quantum mechanics , in vitro , composite material
— The absorption and fluorescence properties of porphyrin c (P c ), the porphyrin chromophore present in cytochrome c , have been determined in several solvents and micellar environments. In aqueous buffer solutions at pH 7.5 Pc may exist in both a fluorescent monomeric form with quantum yield of fluorescence, (Φ f ,) ∼ 0.03, and fluorescence lifetime, (τ f ) ∼ 8 ns, and as a non‐fluorescent aggregate. The proportion of monomeric form is higher in organic solvents and micelles but is reduced with increasing porphyrin concentrations in aqueous solutions. Porphyrin c readily complexes with Zn 2+ to produce a fluorescent chelate (Zn‐P c ) with Φ f , ∼ 0.02 and τ f , ∼ 2 ns at pH 7.5. The yields of singlet excited oxygen formation from Pc and the Zn‐P c complex are higher than observed for hematoporphyrin derivative (HpD). Both P c and Zn‐P c are effective agents in tumor phototherapy and do not induce the prolonged cutaneous photosensitivity observed with the use of HpD.