Interactions of Lysozyme with 6-Amino-4-aryl-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carbonitriles : a Fluorescence Quenching Study
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The interactions between 6-amino-4-aryl-3-methyl-1-phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]pyridine-5-carbonitrile and lysozyme (LYSO) were investigated by using tryptophane fluorescence quenching and 6-amino-4-(2-hydroxyphenyl)-3-methyl-1-phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]pyridine-5-carbonitrile (<b>1</b>) was studied in detail because of its high water solubility. At different temperatures, the quenching constants <i>K</i><sub>SV</sub>, the binding constants <i>K</i> and the binding sites <i>n</i> of LYSO with <b>1</b> were determined and the thermodynamic parameters were calculated. The distance <i>r</i> between tryptophane residues and <b>1</b> was obtained according to the Forster mechanism of non-radiation energy transfer. Furthermore, synchronous fluorescence spectroscopy data indicated that the association between <b>1</b> and LYSO changed LYSO's conformation and that the hydrophobic interaction played a major role in <b>1</b>-LYSO association. It was proved that the fluorescence quenching of LYSO by <b>1</b> was related to the formation of a <b>1</b>-LYSO complex and to a non-radiation energy transfer.
- Analytical Sciences
Analytical Sciences 23(4), 419-422, 2007-04-10
The Japan Society for Analytical Chemistry