title: Interaction of tetramethylpyrazine with two serum albumins by a hybrid spectroscopic method.
abstract: The interactions of tetramethylpyrazine (TMPZ) with bovine serum albumin (BSA) and human serum albumin (HSA) have been investigated by various spectroscopic techniques. Fluorescence tests showed that TMPZ could bind to BSA/HSA to form complexes. The binding constants of TMPZ-BSA and TMPZ-HSA complexes were observed to be 1.442 × 10(4) and 3.302 × 10(4)M(-1) at 298K, respectively. The thermodynamic parameters (ΔG, ΔH and ΔS) calculated on the basis of different temperatures revealed that the binding of TMPZ-HSA was mainly depended on hydrophobic interaction, and yet the binding of TMPZ-BSA might involve hydrophobic interaction strongly and electrostatic interaction. The results of synchronous fluorescence, three-dimensional fluorescence, UV-vis absorption, FT-IR and CD spectra showed that the conformations of both BSA and HSA altered with the addition of TMPZ. The binding average distance between TMPZ and BSA/HSA was evaluated according to Föster non-radioactive energy transfer theory. In addition, with the aid of site markers (such as, phenylbutazone, ibuprofen and digitoxin), TMPZ primarily bound to tryptophan residues of BSA/HSA within site I (sub-domain II A).
authors.affiliation: Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637002, China. ncczj1112@126.com
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D005343:Fibrinolytic Agents / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D030004:Ligusticum / Q000737:chemistry; D011485:Protein Binding; D011719:Pyrazines / Q000737:chemistry / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D005343:Fibrinolytic Agents; D011719:Pyrazines; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; C017953:tetramethylpyrazine