Abstract:

The interaction between amidocaproic acid(ACA) and bovine serum albumin(BSA) was investigated by spectroscopic techniques including fluorescence, UV visible absorption and circular dichroism(CD) spectroscopies under simulative physiological conditions. The fluorescence quenching mechanism of BSA by ACA could be attributed to a dynamic quenching according to the Stern-Volmer equation and UV absorption spectra of BSA. Hydrogen bondings and van der Waals interactions are responsible for their interaction on the basis of the calculated thermodynamic parameters, binding constants and binding site numbers. A 2.3 nm binding distance between ACA and BSA was obtained based on the theory of Forster′s non-radiation energy transfer. From displacement experiments it was identified that ACA binds to protein BSA at site I. Moreover, CD spectra demonstrated that the second structure of BSA induced a slight structural change after binding ACA.

Key words: Amidocaproic acid, Bovine Serum Album, fluorescence quenching, UV-vis, Displacement experiments