Interglobular Diffusion of an Energy Donor in Triplet-Triplet Energy Transfer in Proteins

Abstract

The triplet-triplet energy transfer between polar molecules of luminescent probe (eosin) as an energy donor and nonpolar molecules of energy acceptor (anthracene) is studied. Both the donor and the acceptor are bound to human serum albumin by noncovalent bonds. A dependence of rate constant of triplet-triplet energy transfer on human serum albumin concentration is revealed. A rate constant of eosin output from protein globules is determined. It is shown that the energy transfer occurs as a result of interglobular diffusion of eosin. The obtained results indicate that a protein-luminescent probe based sensor can be used for testing a concentration of polycyclic aromatic hydrocarbons in proteins.