Electrostatic interactions of fluorescein dyes with proteins

The interactions of a number of halogen derivatives of fluorescein with human carbonylhaemoglobin and human serum albumin have been studied. The binding affinities of these proteins were compared with the charge properties of the dyes. The charge properties, determined from titration curves. Hückel molecular orbital (HMO) calculations and the equilibria established between polar and non-polar phase testify to an important role of dipole moments of the halogen derivatives in their interactions with proteins.