Investigation of interaction between alkoxy substituted phthalocyanines with different lengths of alkyl residue and bovine serum albumin

Interaction between bovine serum albumin and alkoxy substituted phthalocyanines was studied by means of electron absorption spectroscopy, fluorescence spectroscopy and viscosimetry. The binding constants and binding distance were calculated. It was found that ZnPc(4-NH-CO-C6H4-OC10H21)4 prevents twisting of BSA molecule and localizes between subdomains IB and IIA in protein globule. ZnPc(4-NH-CO-C6H4-OC6H13)4 and ZnPc(4-NH-CO-C6H4-OC8H17)4 are located on the outer surface of the protein globule. In the case of ZnPc(4-NH-CO-C6H4-OC3H7)4 it can be assumed that the phthalocyanine molecule is in the immediate vicinity of the subdomains IB and IIA.