Study on the interaction between rare earth complex [Er(C18H22.5N2O4)2] and bovine serum albumin

The interaction of rare earth complex [Er(C 18 H 22.5 N 2 O 4 ) 2 ] and bovine serum albumin (BSA) under physiological condition was studied by fluorescence spectrum. The experiment demonstrated that the fluorescence quenching of BSA by Er(III) complex is a result of the formation of ground state complex and the quenching mechanism is mainly static quenching. The corresponding binding constants between Er(III) complex and BSA were 5.17×10 3 L.mol -1 (293K), and the binding sites were 1. According to the binding constants of the different temperatures, the thermodynamic parameters AH, AG, AS were calculated. From thermodynamic parameters it can be judged that the binding force between Er(III) complex and BSA is mainly H-bond and Van der Waals force. The effect of Er(III) complex on the conformation of BSA was analyzed by synchronous fluorescence spectrometry.