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
Quaternaryammonium compounds (QACs) are cationic surfactants with broad range applications. They enter into aquatic environment through the discharge of sewage effluents and adversely affect the ecosystem due to toxic...Quaternaryammonium compounds (QACs) are cationic surfactants with broad range applications. They enter into aquatic environment through the discharge of sewage effluents and adversely affect the ecosystem due to toxicity. Modern electrochemical methods have been used for characterization and detoxification of an extensively used QAC, didodecyldimethylammonium bromide (DDAB) in a wide pH range. The diffusion coefficient of DAAB was determined by Randles-Sevcik equation. In acidic conditions the electrochemical reduction of DAAB occurred by two electrons and two protons process. However, in neutral medium the overall reduction of DAAB followed electronation-protonation mechanism involving 3e– and 3H+. Although DDAB is toxic yet it is bestowed with cancer preventing ability. Hence, for getting insights into the under-standing of DAAB anticancer effect, its DNA binding parameters has been evaluated.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 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
Sevelamer Carbonate is a crossolinked polymeric amine, it is the active ingredient in Renvela Tablets. Sevelamer Carbonate is indicated for the control of hyperphosphatamiea in patients with end-stage renal disease. T...Sevelamer Carbonate is a crossolinked polymeric amine, it is the active ingredient in Renvela Tablets. Sevelamer Carbonate is indicated for the control of hyperphosphatamiea in patients with end-stage renal disease. The binding parameter constants of Sevelamer Carbonate were determined using the Langmuir approximation for the dosage form at pH 4.0 and 7.0 by Ion Chromatography. An Ion Chromatogrpahy method has been developed to estimate free phosphate in in-vitro phosphate binding study of Sevelamer Carbonate Tablets. The method is selective and capable of detecting phosphate in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.2 mM for Phosphate. A linear response function was established in the range of concentrations 0.2 - 30.0 mM (r > 0.99) for Phosphate. The intra and inter day precision values for Phosphate met the acceptance as per Food and Drug Administrations guidelines. Phosphate was stable in the set of stability studies viz. bench-top and autosampler. The developed method was applied to in-vitro phosphate binding studies of Sevelamer Carbonate Tablets.展开更多
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.
文摘Quaternaryammonium compounds (QACs) are cationic surfactants with broad range applications. They enter into aquatic environment through the discharge of sewage effluents and adversely affect the ecosystem due to toxicity. Modern electrochemical methods have been used for characterization and detoxification of an extensively used QAC, didodecyldimethylammonium bromide (DDAB) in a wide pH range. The diffusion coefficient of DAAB was determined by Randles-Sevcik equation. In acidic conditions the electrochemical reduction of DAAB occurred by two electrons and two protons process. However, in neutral medium the overall reduction of DAAB followed electronation-protonation mechanism involving 3e– and 3H+. Although DDAB is toxic yet it is bestowed with cancer preventing ability. Hence, for getting insights into the under-standing of DAAB anticancer effect, its DNA binding parameters has been evaluated.
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 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...
文摘Sevelamer Carbonate is a crossolinked polymeric amine, it is the active ingredient in Renvela Tablets. Sevelamer Carbonate is indicated for the control of hyperphosphatamiea in patients with end-stage renal disease. The binding parameter constants of Sevelamer Carbonate were determined using the Langmuir approximation for the dosage form at pH 4.0 and 7.0 by Ion Chromatography. An Ion Chromatogrpahy method has been developed to estimate free phosphate in in-vitro phosphate binding study of Sevelamer Carbonate Tablets. The method is selective and capable of detecting phosphate in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.2 mM for Phosphate. A linear response function was established in the range of concentrations 0.2 - 30.0 mM (r > 0.99) for Phosphate. The intra and inter day precision values for Phosphate met the acceptance as per Food and Drug Administrations guidelines. Phosphate was stable in the set of stability studies viz. bench-top and autosampler. The developed method was applied to in-vitro phosphate binding studies of Sevelamer Carbonate Tablets.
