[Comparative study of bacteriopheophytin a and b aggregation]

Aggregation of bacteriopheophytins a and b (BPh) in ethanol--glycerol solution and a comparison of spectral properties of obtained aggregated pigment forms were studied. The dependence of aggregation process on percentage of glycerol and pigment concentration on alcohol solution was studied. The aggregation of BPh was followed by very strong deformation of electron absorption and circular dichroism (CD) spectra. Some changes in the first and second electron bands and in Soret region were found. An analysis of BPh a and b aggregates CD spectra shows its general similarity in all spectral regions. It may be connected with structural identity of the obtained aggregated forms. The molar coefficient extinction of BPh aggregates was determined.