title: Interactions of lysozyme with 6-amino-4-aryl-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles: a fluorescence quenching study.
abstract: The interactions between 6-amino-4-aryl-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile and lysozyme (LYSO) were investigated by using tryptophane fluorescence quenching and 6-amino-4-(2-hydroxyphenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitrile (1) was studied in detail because of its high water solubility. At different temperatures, the quenching constants K(SV), the binding constants K and the binding sites n of LYSO with 1 were determined and the thermodynamic parameters were calculated. The distance r between tryptophane residues and 1 was obtained according to the Forster mechanism of non-radiation energy transfer. Furthermore, synchronous fluorescence spectroscopy data indicated that the association between 1 and LYSO changed LYSO's conformation and that the hydrophobic interaction played a major role in 1-LYSO association. It was proved that the fluorescence quenching of LYSO by 1 was related to the formation of a 1-LYSO complex and to a non-radiation energy transfer.
authors.affiliation: Department of Chemistry, Xuzhou Normal University, P. R. China. wuhui72@yahoo.com.cn
authors.forename: Hui
authors.initials: H
authors.lastname: Wu
authors.forename: Shuqin
authors.initials: S
authors.lastname: Lian
authors.forename: Yang
authors.initials: Y
authors.lastname: Shen
authors.forename: Yu
authors.initials: Y
authors.lastname: Wan
mesh_terms: D009113:Muramidase / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D009570:Nitriles; D011720:Pyrazoles; D011725:Pyridines; D014364:Tryptophan; D009113:Muramidase