Interaction of an organic selenium compound with human serum albumin: a spectroscopic study.

The interaction between 4,4′-diselenadibenzoic acid and human serum albumin (HSA) was investigated by fluorescence and absorption spectroscopy. The quenching mechanism of fluorescence of HSA by 4,4′-diselenadibenzoic acid was discussed. It is proved that the fluorescence quenching of HSA by 4,4′-diselenadibenzoic acid is a result of the formation of the HSA-4,4′-diselenadibenzoic acid complex. The binding sites number n, apparent corporation constant K, and corresponding thermodynamic parameters, ΔH ϕ, ΔG ϕ, and ΔS ϕ were calculated. Results indicate that the electrostatic interactions forces played major role in the reaction.