Photo-induced reactions of sulfonated aluminum phthalocyanine with peptide

The photosensitized oxidation mechanism of peptide in the presence of the CIAlPcS is studied by UV-Vis spectroscopic method. It is found that the oxidation of peptide is totally quenched in 1.1 × 10₋₂ molk NaN₃ solution, and the same reaction cannot proceed in the dark. K₃Fe(CN)₆ and L-Cys cannot quench the reaction. Therefore, the reaction mechanism is mainly Foote’s type II. This reaction process can be inferred as follows: (i) active oxygen can attack acylamide bond near by carbon atom; (ii) carboxyl group departs from peptide; (iii) I-benzazole cycle is destroyed when reaction is continued; (iv) the peptide is completely damaged.