SPECTRAL CHARACTERISTICS OF THE AGGREGATION OF ,BETA,GAMMA,DELTA-TETRAKIS(P-SULFOPHENYL)PORPHYRIN IN THE PRESENCE OF PROTEINS

With the aid of absorption, fluorescence, and resonance light-scatteri ng measurements, the aggregation of protonated water-soluble porphyrin , ,beta,gamma,delta-tetrakis(p-sulfophenyl)porphyrin [H(4)tpps(4)](2-) , in the presence of proteins has been characterized. At pH 1.86, prot eins dissolved in water can form a positively charged microphase, whic h can neutralize the negative charges of [H(4)tpps(4)](2-) distributed in it, leading to the J- and H-aggregation of [H(4)tpps(4)](2-). Exci ton splitting signals, which are generally associated with the aggrega tion of porphyrins, as described by molecular-exciton theory, are obse rved at 436.1 nm on the resonance light-scattering spectra, supporting the porphyrin-porphyrin interactions in the positively charged microp hase of proteins. It has been proved that positively charged microphas e can protect aggregates of [H(4)tpps(4)](2-) from water dilution and high temperature.