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Scatchard Plots (scatchard + plot)
Selected AbstractsQuantitative evaluation of the interaction between netropsin and double stranded oligodeoxynucleotides by microfabricated capillary array electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2007Zheng Shen Abstract Microfabricated capillary array electrophoresis (,-CAE) was applied to study the interaction between minor groove binder netropsin and a non-selfcomplementary 12 mer double stranded oligodeoxynucleotide: d(CCCCTATACCGC)·d(GCGGTATAGGGG). ESI-MS was used to provide an independent verification of the microchip electrophoresis derived data. Simultaneous parallel quantitative assay of multiple samples was performed in a single run (<50 s) on the self-developed ,-CAE device. The binding constant and stoichiometry calculated from Scatchard plot were (2.88 ± 0.23)×105 M,1 and 1:1, respectively. The values showed a good quantitative agreement with the results determined by ESI-MS and those using other methods reported in the literature. [source] Simultaneous liquid chromatographic assay of amantadine and its four related compounds in phosphate-buffered saline using 4-fluoro-7-nitro-2,1,3-benzoxadiazole as a fluorescent derivatization reagentBIOMEDICAL CHROMATOGRAPHY, Issue 5 2006Yasuhiko Higashi Abstract Simultaneous HPLC assay of 1-adamantanamine hydrochloride (amantadine) and its four related compounds [2-adamantanamine hydrochloride (2-ADA), 1-adamantanmethylamine (ADAMA), 1-(1-adamantyl)ethylamine hydrochloride (rimantadine) and 3,5-dimethyl-1-adamantanamine hydrochloride (memantine)] in phosphate-buffered saline (pH 7.4) after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed. Phosphate-buffered saline samples were mixed with borate buffer and NBD-F solution in acetonitrile at 60°C for 5 min and injected into HPLC. Five derivatives were well separated from each other. The lower limits of detection of amantadine, 2-ADA, ADAMA, rimantadine and memantine were 0.008, 0.001, 0.0008, 0.0015 and 0.01 µg/mL, respectively. The coefficients of variation for intra- and inter-day assay were less than 6.4 and 8.2%, respectively. The method presented was applied to a binding study of these compounds to human ,1 -acid glycoprotein. While affinity constants and capacities for ADAMA, rimantadine and memantine were calculated by means of Scatchard plots, those for the others were not determined. ADAMA, rimantadine and memantine were bound with different affinities and capacities. These results indicate that NBD-F is a good candidate as a fluorescent reagent to simultaneously determine amantadine and its four related compounds by HPLC after pre-column derivatization. Our method can be applied to binding studies for protein. Copyright © 2005 John Wiley & Sons, Ltd. [source] A spectroscopic investigation into the interactions of 3,- O -carboxy esters of thymidine with bovine serum albuminBIOPOLYMERS, Issue 9 2009Kalyan Sundar Ghosh Abstract Binding studies of 3,-O-carboxy esters of thymidine, reported inhibitors of ribonucleases, with bovine serum albumin (BSA) have been explored in this report. Fluorescence spectroscopy in combination with Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy have been used to determine the nature and mode of binding. The binding and quenching parameters were determined from tryptophan fluorescence quenching by Scatchard plots and modified Stern,Volmer plots. The association constants are of the order of 104 M,1 for both the ligands. Thermodynamic parameters suggest that apart from an initial hydrophobic association, hydrogen bonding and van der Waals interactions play a decisive role during protein-ligand complex formation. Minor changes were observed in the secondary structures of human serum albumin (HSA) as revealed by FTIR and CD. Docking studies suggest that the ligands are close to Trp 213, which causes fluorescence quenching. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 737,744, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Spectroscopic studies of interaction of chlorobenzylidine with DNABIOPOLYMERS, Issue 6 2001Wenying Zhong Abstract Electronic absorbance and fluorescence titrations are used to probe the interaction of chlorobenzylidine with DNA. The binding of chlorobenzylidine to DNA results in hypochromism, a small shift to a longer wavelength in the absorption spectra, and emission quenching in the fluorescence spectra. These spectral characteristics suggest that chlorobenzylidine binds to DNA by an intercalative mode. This conclusion is reinforced by fluorescence polarization measurements. Scatchard plots constructed from fluorescence titration data give a binding constant of 1.3 × 105M,1 and a binding site size of 10 base pairs. This indicates that chlorobenzylidine has a high affinity with DNA. The intercalative interaction is exothermic with a Van't Hoff enthalpy of ,143 kJ/mol. This result is obtained from the temperature dependence of the binding constant. The interaction of chlorobenzylidine with DNA is affected by the pH value of the solution. The binding constant has its maximum at pH 3.0. Upon binding to DNA, the fluorescence from chlorobenzylidine is quenched efficiently by the DNA bases and the fluorescence intensity tends to be constant at high concentrations of DNA when the binding is saturated. The Stern,Volmer quenching constant obtained from the linear quenching plot is 1.6 × 104M,1 at 25°C. The measurements of the fluorescence lifetime and the dependence of the quenching constant on the temperature indicate that the fluorescence quenching process is static. The fluorescence lifetime of chlorobenzylidine is 1.9 ± 0.4 ns. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 315,323, 2001 [source] | ||||||||||