TYPES I AND II SENSITIZED PHOTOOXIDATION OF AMINOACID BY PHTHALOCYANINES: A FLASH PHOTOCHEMICAL STUDY |
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| Authors: | G Ferraudi G A Arguello H Ali J E VAN Lier |
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| Institution: | Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA;MRC Group in the Radiation Sciences, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada |
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| Abstract: | Abstract— In connection with the use of red light-photosensitizers for photodynamic therapy, the redox reactivity of excited metallophthalocyanines (M = Al, Ga) was investigated by flash photolysis in order to establish whether photooxidations proceed by Foote's mechanisms I or II. Aminoacids (tryptophan, tyrosine) were seen to function as electron transfer quenchers of the excited phthalocyanines with rate constants 107 k 104 M -1 s-1. This was not the case of purines or ATP. The ability of the excited phthalocyanines to sensitize photooxidations by mechanisms I and II is discussed in terms of evaluated rate constants. |
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