Study on the Interaction of Nd³⁺ with Human Serum Albumin at Molecular Level

Abstract

Neodymium is applied widely in agriculture to improve crop nutrition and incidentally in fertilizers, yet little is known of its effect on the biological function of human serum albumin (HSA). The interaction of Nd 3+ to HSA has been investigated mainly by fluorescence spectra, UV-vis absorption spectra and circular dichroism (CD) under simulative physiological conditions. Fluorescence data revealed that the quenching mechanism of HSA by Nd 3+ was a static quenching process and the binding constant is 5.71 × 10 4 L mol -1 and the number of binding sites is 1 at 292 K. The thermodynamic parameters (DH 0 = -20.79 kJ mol -1 , DG 0 = -26.58 kJ mol -1 , and DS 0 = 19.85 J mol -1 K -1 ) indicate that electrostatic effect between the protein and Nd 3+ is the main binding force. The distance r = 2.91 nm between donor (HSA) and acceptor (Nd 3+ ) was obtained according to Förster's nonradiative energy transfer. In addition, UV-vis, CD and synchronous fluorescence results showed that the addition of Nd 3+ changed the conformation of HSA.

Study on the luminescence behavior of lanthanide ions with luminol by flow injection chemiluminescence analysis

“…By the home-made FI-CL model [46], the binding constants K D and the number of binding sites n of BSA with La III , Eu III , Gd III , Tb III and Lu III are listed in Table 6. It could be seen K D were at 10 4 -10 5 level, suggesting that there existed a high binding affinity of Ln III to BSA, which agreed well with the results obtained by fluorescence quenching method [47][48][49]. The binding ability of Ln III increased in the sequence: La III oEu III oGd III o Tb III oLu III , which was highly related to Ln III expansion-inducing ability increased and steric effect decreased caused by lanthanide contraction [50].…”