title: [Spatial orientation interaction mechanism between chondroitin sulfate and azure A].
abstract: The spatial orientation interaction mechanism of chondroitin sulfate (CS) and azure A (AA) was studied by spectrometry. The maximum binding number (N = 151) and the binding equilibrium constant (K = 5. 24 x 10(4)) were obtained. The molecular binding model of the interaction between AA and CS was established. The influence of the molar ratio of AA/CS, ethanol, hydroxypropyl-beta-cyclodextrin, triton X-100 and NaCl on the spectra of AA-CS complex was investigated. We conclude that the color change of complex depends on not only the electrostatic interaction between AA and CS but also the density of AA binding on CS. And the formation of the absorption peak at 550 nm and the color change of complex result mainly from the hydrophobic interaction between AA and AA binding on CS.
authors.affiliation: Pharmaceutic Biotechnology Key Laboratory, College of Life Science, Nanjing University, Nanjing 210093, China.
authors.forename: Wen-gen
authors.initials: WG
authors.lastname: Cao
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Qing-cai
authors.initials: QC
authors.lastname: Jiao
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Ding
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D001399:Azure Stains / Q000737:chemistry*; D002809:Chondroitin Sulfates / Q000737:chemistry*; D003505:Cyclodextrins; D004347:Drug Interactions; D000431:Ethanol; D008958:Models, Molecular; D015394:Molecular Structure; D013053:Spectrophotometry / Q000379:methods; D013056:Spectrophotometry, Ultraviolet; D047392:beta-Cyclodextrins
chemical_list: D001399:Azure Stains; D003505:Cyclodextrins; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000431:Ethanol; D002809:Chondroitin Sulfates; C025818:Azure A