Cyanide ion was studied as an effector of Jack bean urease(JBU) at 300 K in 30 mmol/LTris buffer,pH 7 by isothermal titration calorimetry(ITC).The simple novel model was used for CN^- + JBU interaction over the whole ...Cyanide ion was studied as an effector of Jack bean urease(JBU) at 300 K in 30 mmol/LTris buffer,pH 7 by isothermal titration calorimetry(ITC).The simple novel model was used for CN^- + JBU interaction over the whole range of CN^- concentrations.The binding parameters recovered from the simple novel model were attributed to the cyanide ion interaction.It was found that cyanide ion acted as a noncooperative inhibitor of JBU,and there is a set of 12 identical and independent binding sites for CN^- ions.The di...展开更多
A method was established using hollow fiber-liquid phase microextraction（HF-LPME） followed by high performance liquid chromatography（HPLC） to determine the concentration of the free（unbound） drug in the solution...A method was established using hollow fiber-liquid phase microextraction（HF-LPME） followed by high performance liquid chromatography（HPLC） to determine the concentration of the free（unbound） drug in the solution of the drug and protein. Measurements of drug-protein binding ratios and free drug concentrations were then analyzed with the Klotz equation to determine the equilibrium binding constant and number of binding sites for drug-protein interaction. The optimized method allows one to perform the efficient extraction and separation of free drug from protein-bound drug, protein, and other interfering substances. This approach was used to characterize the binding of the anticholinergic drugs atropine sulfate and scopolamine hydrobromide to proteins in human plasma and bovine serum albumin（BSA）. The results demonstrate the utility of HF-LPME method for measuring free drug concentrations in protein-drug mixtures and determining the protein binding parameters of a pharmacologically important class of drugs.展开更多
Cyanide ion was studied as an inhibitor of Jack bean urease at 300 K in 30 mmol/L tris buffer, pH 7. The inhibition was investigated by isothermal titration calorimetry （ITC）. The extended solvation model was used f...Cyanide ion was studied as an inhibitor of Jack bean urease at 300 K in 30 mmol/L tris buffer, pH 7. The inhibition was investigated by isothermal titration calorimetry （ITC）. The extended solvation model was used for CN^- ＋ JBU interaction over the whole range of CN^- concentrations. The binding parameters recovered from the solvation model were attributed to the cyanide ion interaction. It was found that cyanide ion acted as a non-cooperative inhibitor ofurease, and there is a set of 12 ± 0.12 identical and independent binding sites for CN- ions. The dissociation equilibrium constant is 749.99 umol/L. The molar enthalpy of binding is AH= -13.60 kJ mol^-1.展开更多
A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calonmetry,ITC,at 300.15,310.15 and 320.15 K in Tris buffer solution at pH 7.The enthalpies o...A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calonmetry,ITC,at 300.15,310.15 and 320.15 K in Tris buffer solution at pH 7.The enthalpies of MBP ＋ Hg^（2＋） interaction are reported and analysed in terms of the extended solvation model.It was found that MBP has two identical and non-cooperative binding sites for Hg^（2＋） ions.The intrinsic dissociation equilibrium constants are 99.904,112.968 and 126.724μmol/L,and the molar enthalpy of binding are -11.634,-10.768 and -10.117kJ mol^（-1） at 300.15,310.15 and 320.15 K,respectively.展开更多
The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were hi...The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure.展开更多
文摘Cyanide ion was studied as an effector of Jack bean urease(JBU) at 300 K in 30 mmol/LTris buffer,pH 7 by isothermal titration calorimetry(ITC).The simple novel model was used for CN^- + JBU interaction over the whole range of CN^- concentrations.The binding parameters recovered from the simple novel model were attributed to the cyanide ion interaction.It was found that cyanide ion acted as a noncooperative inhibitor of JBU,and there is a set of 12 identical and independent binding sites for CN^- ions.The di...
基金Supported by the National Natural Science Foundation of China(No.81041084)the Natural Science Foundation of Shanxi Province, China(No.2007011086)the Undergraduate Innovation Fund of Taiyuan City, China(No.08122034)
文摘A method was established using hollow fiber-liquid phase microextraction（HF-LPME） followed by high performance liquid chromatography（HPLC） to determine the concentration of the free（unbound） drug in the solution of the drug and protein. Measurements of drug-protein binding ratios and free drug concentrations were then analyzed with the Klotz equation to determine the equilibrium binding constant and number of binding sites for drug-protein interaction. The optimized method allows one to perform the efficient extraction and separation of free drug from protein-bound drug, protein, and other interfering substances. This approach was used to characterize the binding of the anticholinergic drugs atropine sulfate and scopolamine hydrobromide to proteins in human plasma and bovine serum albumin（BSA）. The results demonstrate the utility of HF-LPME method for measuring free drug concentrations in protein-drug mixtures and determining the protein binding parameters of a pharmacologically important class of drugs.
文摘Cyanide ion was studied as an inhibitor of Jack bean urease at 300 K in 30 mmol/L tris buffer, pH 7. The inhibition was investigated by isothermal titration calorimetry （ITC）. The extended solvation model was used for CN^- ＋ JBU interaction over the whole range of CN^- concentrations. The binding parameters recovered from the solvation model were attributed to the cyanide ion interaction. It was found that cyanide ion acted as a non-cooperative inhibitor ofurease, and there is a set of 12 ± 0.12 identical and independent binding sites for CN- ions. The dissociation equilibrium constant is 749.99 umol/L. The molar enthalpy of binding is AH= -13.60 kJ mol^-1.
文摘A thermodynamic study on the interaction of myelin basic protein with mercury ion was studied by using isothermal titration calonmetry,ITC,at 300.15,310.15 and 320.15 K in Tris buffer solution at pH 7.The enthalpies of MBP ＋ Hg^（2＋） interaction are reported and analysed in terms of the extended solvation model.It was found that MBP has two identical and non-cooperative binding sites for Hg^（2＋） ions.The intrinsic dissociation equilibrium constants are 99.904,112.968 and 126.724μmol/L,and the molar enthalpy of binding are -11.634,-10.768 and -10.117kJ mol^（-1） at 300.15,310.15 and 320.15 K,respectively.
基金financially supported by the National Natural Science Foundation of China(21175041)the National Basic Research Program of China(2012CB910602)
文摘The interaction between BSA and epicatechin was studied using fluorescence quenching titrations combined with trilinear decomposition method and excitation-emission matrix(EEM)fluorescence.The resolved spectra were highly similar with the actual ones which indicated that the resolved results were reliable.The relevant parameters of the binding process were obtained by quantifying each substance in the complicated mixtures in situ.The quenching was static quenching,epicatechin had a weak interaction with BSA and the binding site was one.The total concentration and the free concentration of quenchers had different effect on the system.The results demonstrated that the method exploited in this article is a useful tool to investigate complicated interactions,avoiding complicated pretreatment and simplify experimental procedure.
