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Interaction of cyproheptadine hydrochloride with human serum albumin using spectroscopy and molecular modeling methods
Author(s) -
Jiang Hua,
Chen Rongrong,
Wang Hongcui,
Pu Hanlin
Publication year - 2012
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.2374
Subject(s) - chemistry , human serum albumin , cyproheptadine , fluorescence spectroscopy , quenching (fluorescence) , spectroscopy , fourier transform infrared spectroscopy , fluorescence , binding constant , hydrophobic effect , absorption spectroscopy , infrared spectroscopy , molecular model , analytical chemistry (journal) , crystallography , binding site , stereochemistry , chromatography , organic chemistry , biochemistry , physics , receptor , quantum mechanics , serotonin
ABSTRACT The interaction between cyproheptadine hydrochloride (CYP) and human serum albumin (HSA) was investigated by fluorescence spectroscopy, UV–vis absorption spectroscopy, Fourier transform infrared spectroscopy (FT‐IR) and molecular modeling at a physiological pH (7.40). Fluorescence of HSA was quenched remarkably by CYP and the quenching mechanism was considered as static quenching since it formed a complex. The association constants K a and number of binding sites n were calculated at different temperatures. According to Förster's theory of non‐radiation energy transfer, the distance r between donor (human serum albumin) and acceptor (cyproheptadine hydrochloride) was obtained. The effect of common ions on the binding constant was also investigated. The effect of CYP on the conformation of HSA was analyzed using FT‐IR, synchronous fluorescence spectroscopy and 3D fluorescence spectra. The thermodynamic parameters Δ H and Δ S were calculated to be −14.37 kJ mol −1 and 38.03 J mol −1 K −1 , respectively, which suggested that hydrophobic forces played a major role in stabilizing the HSA‐CYP complex. In addition, examination of molecular modeling indicated that CYP could bind to site I of HSA and that hydrophobic interaction was the major acting force, which was in agreement with binding mode studies. Copyright © 2012 John Wiley & Sons, Ltd.