Spectrometric investigations on the binding of dopamine to bovine serum albumin

The binding of dopamine (DA) with bovine serum albumin (BSA) was investigated for the first time by fluorescence and Fourier transform–infrared spectroscopy. The association constants, thermodynamic parameters, quenching rate constants at three different temperatures and the number of binding sites were also determined. The fluorescence results revealed that the fluorescence of BSA was quenched by DA through a static quenching procedure and a DA–BSA complex was formed. Synchronous fluorescence spectroscopy illustrated that DA interacted with both tyrosine residues and tryptophan residues of BSA. IR spectra revealed the structure changes of the BSA functional groups with the addition of DA. The thermodynamic study and IR spectra confirmed that hydrophobic and hydrogen bonds interactions were both the predominant intermolecular forces to stabilise the complex.