title: Interaction between azo dye Acid Red 14 and pepsin by multispectral methods and docking studies.
abstract: The interaction of synthetic azo dye Acid Red 14 with pepsin was studied by fluorescence spectroscopy, UV-vis spectroscopy, circular dichroism and molecular docking. Results from the fluorescence spectroscopy show that Acid Red 14 has a strong capability to quench the intrinsic fluorescence of pepsin with static quenching. Binding constant, number of the binding sites and thermodynamic parameters were measured at different temperatures. The result indicates that Acid Red 14 interact with pepsin spontaneously by hydrogen bonding and van der Waals interactions. Three-dimensional fluorescence spectra and circular dichroism spectra reveal that Acid Red 14 could slightly change the structure of pepsin. The hydrogen bond is formed between Acid Red 14 and Tyr-189 and Thr-218 residues of pepsin. Furthermore, the binding between Acid Red 14 and pepsin inhibits pepsin activity. The study can provide a way to analyze the biological safety of Acid Red 14 on digestive proteases or other proteins.
authors.affiliation: College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu, China.
authors.forename: Ludan
authors.initials: L
authors.lastname: Zhao
authors.affiliation: College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu, China.
authors.forename: Ronghui
authors.initials: R
authors.lastname: Guo
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu, China.
authors.forename: Qiaomei
authors.initials: Q
authors.lastname: Sun
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu, China.
authors.forename: Jianwu
authors.initials: J
authors.lastname: Lan
authors.affiliation: College of Chemical Engineering, Sichuan University, Chengdu, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D001391:Azo Compounds / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002942:Circular Dichroism; D006860:Hydrogen Bonding; D062105:Molecular Docking Simulation; D010434:Pepsin A / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: C469409:Acid red 14; D001391:Azo Compounds; D010434:Pepsin A
keywords: Acid Red 14; circular dichroism; molecular modeling; pepsin; spectroscopy