Effect of diphenylalanine on the functional activity of porphyrin and non-porphyrin photosensitizers solubilized by Pluronic F127

Abstract

Abstract The effect of the diphenylalanine (Phe-Phe) amino acid on the rate of tryptophan photooxidation catalyzed by photosensitizers (PS) of different natures: dimegin (DMG), fluorinated tetraphenylporphyrin (FTPP), photoditazine (PD) and methylene blue (MB) was studied. It was shown that in the presence of Phe-Phe, the effective constant of photooxidation of the substrate catalyzed by DMG, PD and MB in the aqueous phase decreases. However, the introduction of the amphiphilic polymer Pluronic F127 into the systems allows not only to restore, but also to increase the activity of the PS in the processes of photosensitized oxidation. In particular, the activity of dimegin solubilized by Pluronic F127 in the presence of Phe-Phe is higher than the activity of both pure porphyrin and solubilized DMG. In addition, the activity of the hydrophobic FTPP solubilized by Pluronic also increases. At the same time, a study of the luminescence of singlet oxygen generated by solubilized FTPP in the absence and presence of Phe-Phe revealed that the dipeptide does not influence the processes of 1О2 generation. It was suggested that micellar catalysis influences the activity of solubilized PS in the presence of a biologically active dipeptide.