Spectroscopic investigation of the interaction between riboflavin and bovine serum albumin

In this paper, the binding reaction between riboflavin (RF) and bovine serum albumin (BSA) was studied by using fluorescence spectra and absorption spectra. It is shown that RF has a powerful ability to quench the fluorescence intensity of BSA. The fluorescence quenching data were analyzed according to Stern–Volmer equation and the results indicate that the quenching mechanism is a static quenching procedure and the bind mode various with the concentration of RF. When the concentration of RF is lower, RF combine with the 134 and 214 Trp of BSA though the hydrophobic force or hydrogen bond while the binding sites of RF to BSA are decreased to 1 but the distance shortened when the concentration of RF is higher. It is assumed that RF combines to the 214 Trp of BSA through electronic force.