Characterization of the Interaction between Cationic Thulium (III)–Porphyrin Complex with Bovine Serum Albumin.
- *Corresponding Author:
- Xi-Liang Lu
Department of Chemistry, Guilin Normal College
Guilin GuangXi 541002, PR China
E-mail: [email protected]
Received date: February 16, 2012; Accepted date: April 05, 2012; Published date: April 09, 2012
Citation: Lu XL, Yang HC, Wu H, Hou AX (2012) Characterization of the Interaction between Cationic Thulium (III)–Porphyrin Complex with Bovine Serum Albumin. J Mol Biomark Diagn 2:126. doi:10.4172/2155-9929.1000126
Copyright: © 2012 Lu XL, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The interaction of cationic Thulium (III)–porphyrin complex(Tm–Porp) with Bovine Serum Albumin (BSA) has been investigated by fluorescence quenching spectra. The quenching mechanism of fluorescence was suggested as a static quenching with a highaffinity according to the Stern–Volmer equation. The number of binding sites and the apparent binding constant a K of the Tm–Porp on BSA were explained by a modified Scatchard equation and the site probe competition. The corresponding thermodynamic parameters ΔH0 ,ΔG0 and ΔS0 at different temperatures are discussed. The results indicated that the electrostatic and hydrophobic interactions are the predominant intermolecular forces in stabilizing complex. Binding distance between the donor and acceptor was obtained in terms of Forester’s Non-radiative energy transfer theory. Furthermore, the effects of the Tm-Porp on the BSA configuration were elucidated by Circular Dichroism (CD) spectra method along with UV–Vis absorption and Synchronous Fluorescence Spectroscopy (SFS). The results indicated that the secondary structures of BSA have been perturbed in the presence of drug. Finally, we showed that the cationic Tm–Porp can preferentially bind at the site-I and site-II of BSA with equal occupancy.