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Fluorescence Quenching Study on the Interaction of Some Schiff Base Complexes with Bovine Serum Albumin
Author(s) -
MEI Ping,
ZHANG LiXi,
LIU Yi,
CAI LiHua,
HU PeiZhi
Publication year - 2008
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200890042
Subject(s) - chemistry , ionic strength , quenching (fluorescence) , schiff base , bovine serum albumin , ligand (biochemistry) , binding constant , ionic bonding , fluorescence , metal , inorganic chemistry , aqueous solution , ion , crystallography , binding site , chromatography , organic chemistry , biochemistry , physics , receptor , quantum mechanics
The interaction of Schiff base ligand A and its three metal complexes [A‐Fe(II), A‐Cu(II), and A‐Zn(II)] with bovine serum albumin (BSA) was investigated using a tryptophan fluorescence quenching method. The Schiff base ligand A and its three metal complexes all showed quenching of BSA fluorescence in a Tris‐HCl buffer. Quenching constants were determined for quenching BSA by the Schiff base ligand A and its metal complexes in a Tris‐HCl buffer (pH=7.4) at different temperatures. The experimental results show that the dynamic quenching constant ( K SV ) was increased with increasing temperature, whereas the association constant ( K ) was decreased with the increase of temperature. The thermodynamic parameters Δ H , Δ G and Δ S at different temperatures were calculated. The ionic strength of the Tris‐HCl buffer had a great influence on the wavelength of maximum emission of BSA. Under low ionic strength, the emission spectra of BSA influenced by A‐Zn(II) had a small blue shift. Compared to A‐Zn(II), the emission spectra of BSA in the presence of the Schiff base ligand A and A‐Cu(II) had no significant λ em shift. At high ionic strength, the emission spectra of BSA upon addition of the Schiff base A, A‐Fe(II), and A‐Zn(II) all had a red shift, but the emission spectra of BSA had λ em shift neither at low ionic strength, nor at high ionic strength in the presence of A‐Cu(II). Furthermore, the temperature did not affect the λ em shift of BSA emission spectra.