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1.
A New Approach for Titration Calorimetric Data Analysis on the Binding of Magnesium Ion with Myelin Basic Protein 总被引:1,自引:0,他引:1
G. Rezaei Behbehani A. A. Saboury A. Fallah Baghery 《Journal of solution chemistry》2008,37(8):1127-1135
The interaction of the myelin basic protein (MBP) from the bovine central nervous system with divalent magnesium ion was studied
by isothermal titration calorimetry at 27 °C in aqueous solution. A simple rapid method for determination of the dissociation
binding constants for Mg2+-MBP interaction was introduced using the isothermal titration calometric data. The binding isotherm for Mg2+-MBP interaction is easily obtained by carrying out a titration calorimetric experiment using only one set of concentrations
of MBP. There are two identical independent intrinsic association constants equal to 0.021 μmol⋅L−1 in the first- and second-binding sites, respectively. 相似文献
2.
G. Rezaei Behbehani A. A. Saboury A. Fallah Baghery A. Abedini 《Journal of Thermal Analysis and Calorimetry》2008,93(2):479-483
Binding properties of myelin basic protein (MBP) from bovine central nervous system due to the interaction by divalent magnesium
ion (Mg2+) was investigated at 27°C in aqueous solution using isothermal titration calorimetry (ITC) technique. An extended solvation
model was used to reproduce the enthalpies of Mg2+-MBP interaction over the whole Mg2+ concentrations. It was found that there is a set of two identical and noninteracting binding sites for Mg2+ ions. The dissociation equilibrium constant is K
d=45.5 μM. The molar enthalpy of binding site is identical for both sites; ΔH=−15.24 kJ mol−1. The solvation parameters recovered from the solvation model were attributed to the structural change of MBP due to the metal
ion interaction. 相似文献
3.
G. Rezaei Behbehani A. A. Saboury A. Fallah Baghery 《Journal of solution chemistry》2007,36(10):1311-1320
The interaction of myelin basic protein (MBP) from the bovine central nervous system with divalent calcium ion was studied
by isothermal titration calorimetry at 27 °C in aqueous solution. The extended solvation model was used to reproduce the enthalpies
of Ca2+-MBP interaction over the whole range of Ca2+ concentrations. The solvation parameters recovered from the solvation model were attributed to the structural change of MBP
due to the metal ion interaction. It was found that there is a set of two identical and non-interacting binding sites for
Ca2+ ions. The association equilibrium constant is 0.021 μmol⋅dm−3. The molar enthalpy of binding is ΔH=−15.10 kJ⋅mol−1. 相似文献
4.
G. Rezaei Behbehani 《中国化学快报》2009,20(6)
The interaction of CuC12 to the first 16 residues of the Alzbeimer's amyliod β peptide, Aβ(1-16) was studied by isothermal titration calorimetry at pH 7.2 and 37 ℃ in aqueous solution. 相似文献
5.
G.Rezaei Behbehani A.A.Saboury M.Mohebbian S.Tahmasbi Sarvestani M.Poorheravi 《中国化学快报》2009,20(11):1389-1392
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 of urease,and there is a set of 12±0.12 identical and in... 相似文献
6.
Mercury ion interaction with myelin basic protein (MBP) was studied at 300 K in 30 mmol/L tris buffer, pH=7 by isothermal titration calorimetry (ITC). An extended solvation model was used for Hg2++MBP interaction over the whole range of Hg2+ concentrations. The binding parameters recovered from the solvation model were attributed to the structural changes of MBP due to its interaction with mercury ion. It was found that mercury ion acted as a noncooperative effector of MBP, and there is a set of two identical and independent binding sites for Hg2+ ions. The dissociation equilibrium constant is 97.6 µmol/L. The molar enthalpy change of binding is ?11.25 kJ·mol?1. 相似文献
7.
<正>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 dissociation equilibrium constant is 750μmol/L.The molar enthalpy of binding is△H= -13.6 kJ mol~(-1).The technique used provided an accurate and quick assessment of the effectiveness of the compounds to inhibit Jack bean urease. 相似文献
8.
G. Rezaei Behbehani A. A. Saboury L. Barzegar O. Zarean J. Abedini M. Payehghdr 《Journal of Thermal Analysis and Calorimetry》2010,101(1):379-384
The interaction of myelin basic protein (MBP) from the bovine central nervous system with divalent nickel ion was studied
by isothermal titration calorimetry at 37 and 47 °C in Tris buffer solution at pH = 7. The new solvation model was used to
reproduce the heats of MBP + Ni2+ interaction over the whole Ni2+ concentrations. It was found that MBP has three identical and independent binding sites for Ni2+ ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 89.953 μM, −14.403 kJ mol−1 and 106.978 μM, −14.026 kJ mol−1 at 37 and 47 °C, respectively. The binding parameters recovered from the new solvation model were correlated to the structural
changes of MBP due to its interaction with nickel ion interaction. It was found that in the low and high concentrations of
the nickel ions, the MBP structure was destabilized. 相似文献
9.
Lu Y Wang G Tang W Hao X Xu M Li X 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):247-252
The binding properties of amino phosphate ester derivatives, compound 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV spectra, fluorescence spectra, molecular modeling and isothermal titration calorimetry (ITC). The intrinsic binding constants Kb of compound 1 and 2 with CT-DNA were determined by fluorescence spectroscopy and ITC, respectively. The results indicated that the two compounds bind to CT-DNA with different binding affinity, which is in the order of compound 1 > compound 2. At the same time, fluorescence spectra suggested that the mechanism of the binding of the two compounds to CT-DNA is a static enhancing type. According to the ethidium bromide displacement experiments, UV spectra, molecular modeling and ITC studies, it can be concluded that compound 1 and 2 are intercalators that can slide into the G–C rich region of CT-DNA. Furthermore, ITC data showed that compound/DNA binding is enthalpy controlled. 相似文献
10.
本文通过Langmuir单层膜的表面压力-平均分子面积(π-A)曲线的测定与分析,分别对髓鞘碱性蛋白(MBP)与细胞膜中不同头部基团脂质分子二棕榈酰基磷脂胆碱(DPPC)和二棕榈酰基磷脂酰乙醇胺(DPPE)在空气/液体界面上的相互作用过程进行了系统研究.实验结果表明:(1)当界面上脂质含量一定时,亚相中随着MBP浓度的增大,DPPC、DPPE单层膜的等温线向平均分子面积较大的方向移动;(2)在单层膜表面压力为10 mN/m时,一个MBP分子分别结合140±3个DPPC分子和100±3个DPPE分子,随着表面压力增大,当MBP分子分别与两种磷脂分子相互作用时,MBP插入到磷脂单层界面的个数逐渐减少;(3)随着蛋白质浓度的增加,脂分子形成的单层膜变得较为疏松,且MBP分子易于插入到分子头部较小的DPPE单层膜中;(4)蛋白质的存在使DPPC单层膜的表面压力逐渐减小,且蛋白质浓度越大表面压力降低越多,DPPC被MBP带入到亚相中越多;(5)对于DPPE单层膜,蛋白质通过与DPPE相互作用插入到界面膜中,引起表面压力增大,且蛋白质浓度越高,压力变化量越大. 相似文献
11.
An optical sensor for mercury ion (Hg2+), based on quenching the fluorescence of the sensing reagent porphyrin immobilized in plasticized poly(vinyl chloride) (PVC) membrane, has been developed. The responses to mercury ion were compared for the sensors modified with three porphyrin compounds including 5,10,15,20-tetraphenylporphyrin (TPP), tetra(p-dimethylaminophenyl)porphyrin (TDMAPP) and tetra(N-phenylpyrazole) porphyrin (TPPP). Among them, TDMAPP showed the most remarkable response to Hg2+. The drastic decrease of the TDMAPP fluorescence intensity was attributed to the formation of a complex between TDMAPP and Hg2+, which has been utilized as the fabrication basis of a Hg2+-sensitive fluorescence sensor. The analytical performance characteristics of the TDMAPP modified sensor was investigated. The response mechanism, especially involving the response difference of three porphyrin compounds, was discussed in detail. The sensor can be applied to the quantification of Hg2+ with a linear range covering from 4.0 × 10−8 mol L−1 to 4.0 × 10−6 mol L−1. The limit of detection was 8.0 × 10−9 mol L−1. The sensor exhibited excellent reproducibility, reversibility and selectivity. Also, the TDMAPP-based sensor was successfully used for the determination of Hg2+ in environmental water samples. 相似文献
12.
Heavy metal ion pollution poses severe risks in human health and environmental pollutant, because of the likelihood of bioaccumulation and toxicity. Driven by the requirement to monitor trace-level mercury ion (Hg2+), herein we construct a new DNA-based sensor for sensitive electrochemical monitoring of Hg2+ by coupling target-induced formation of gold amalgamation on DNA-based sensing platform with gold amalgamation-catalyzed cycling signal amplification strategy. The sensor was simply prepared by covalent conjugation of aminated poly-T(25) oligonucleotide onto the glassy carbon electrode by typical carbodiimide coupling. Upon introduction of target analyte, Hg2+ ion was intercalated into the DNA polyion complex membrane based on T–Hg2+–T coordination chemistry. The chelated Hg2+ ion could induce the formation of gold amalgamation, which could catalyze the p-nitrophenol with the aid of NaBH4 and Ru(NH3)63+ for cycling signal amplification. Experimental results indicated that the electronic signal of our system increased with the increasing Hg2+ level in the sample, and has a detection limit of 0.02 nM with a dynamic range of up to 1000 nM Hg2+. The strategy afforded exquisite selectivity for Hg2+ against other environmentally related metal ions. In addition, the methodology was evaluated for the analysis of Hg2+ in spiked tap-water samples, and the recovery was 87.9–113.8%. 相似文献
13.
14.
G. Rezaei Behbehani A. Divsalar A. A. Saboury F. Faridbod M. R. Ganjali 《Journal of Thermal Analysis and Calorimetry》2009,96(2):663-668
Thermodynamics of the interaction between erbium(III) chloride, Er3+, with human serum albumin (HSA), was investigated at pH 7.0 and in phosphate buffer by isothermal titration calorimetry.
Our recently, solvation model was used to reproduce the enthalpies of HSA interaction by Er3+ over a broad range of metal ion concentration. The solvation parameters recovered from our new model, attributed to the structural
change of HSA and its biological activity. The binding parameters for the interaction of Er3+ and HSA indicate that the concentrations of Er3+ have no significant effects on the structure of HSA. 相似文献
15.
16.
Metallothionein, a class of low molecular weight, metal- and cysteine-rich Proteins, are postulated to play a central role in metal-related biological processes such as the detoxification of Cd2+and Pb2+. The thermal Properties of the interactions of rabbit liver Zn_7MT2 and apo-MT2 with Cd2+ and Pb2+ were studied using isothermal titration calorimeter. The same product Cd_7MT formed in the reactions of Cd2+ with Zn_7MT2 and apo-MT2, while the reactions of Ph2+ with Zn_7MT2 and apo-MT2 Produced two MT species Ph_7MT and Ph_7MT'. The thermodynamic parameters (△H、 △G、 △S, etc. ) for the reactions of MT with 1 mol metal ions were measured at 293.15 K, pH 4.70. All of these reactions are spontaneous, exothermic processes. The values of △G and K show that Cd2+ is more affinitive to MT than Ph2+. The equilibrium constants K of the replacement reactions of Zn_7MT2 by 1 mol Cd2+ and Pb2+ are 2. 7×105 and 1. 3×105 respectively, that means the concentrations of free Cd2+ and Pb2+ are depressed to about 1. 0×10-5 after the reactions with Zn_7MT2. These data can be used to evaluate quantitatively the ability of MT in Cd2+ and Pb2+ detoxificatio. 相似文献
17.
In this article, a thermodynamic study on the interaction of Jack bean urease, JBU, with
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions were studied by isothermal titration calorimetry (ITC) at 300 and 310 K in 30 mM Tris buffer solution, pH 7.0. The heats
of
\textJBU + \textHg 2+ {\text{JBU}} + {\text{Hg}}^{ 2+ } and
\textJBU + \textAg + {\text{JBU}} + {\text{Ag}}^{ + } interactions are reported and analyzed in terms of the extended solvation model. It was indicated that there are a set of
12 identical and non-cooperative sites for
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions. The binding of
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions with JBU are exothermic with association equilibrium constants of 5415.65 and 4368.15 for
\textAg + {\text{Ag}}^{ + } and 2389 and 2087 M - 1 M^{ - 1} for
\textHg 2+ {\text{Hg}}^{ 2+ } at 300 and 310 K, respectively. 相似文献
18.
A. A. Saboury 《Thermochimica Acta》1998,320(1-2):97-100
A simple, novel method was introduced for determining equilibrium constants and enthalpies of binding of two different competitive ligands on a macromolecule by isothermal titration microcalorimetry technique. This method was applied to the simultaneous binding of ethylurea (I) and (N,N)dimethylurea (X), on jack-bean urease at pH 7.0 (tris-base; 30 mM) at 27°C. The dissociation equilibrium constants measured by this method were markedly consistent with inhibition constants obtained from assay of enzyme activities in the presence of I and X. 相似文献
19.
G. Rezaei Behbehani A. Divsalar A. A. Saboury A. Hekmat 《Journal of solution chemistry》2009,38(2):219-229
The thermodynamics of the interaction between a copolymer of polyethyleneglycol400-stearic acid, S400, and lysozyme was investigated
at pH=7.0 and 27 °C in phosphate buffer by isothermal titration calorimetry, ITC. The extended solvation model was used to
reproduce the enthalpies of the S400 + lysozyme interactions. The solvation parameters recovered from the extended solvation
model are attributed to the structural change of lysozyme and its biological activity. The binding parameters found for the
interaction of S400 with lysozyme indicate that at low concentrations of S400, the lysozyme structure was destabilized but
at higher concentrations of S400 lysozyme it was stabilized by S400. It is suggested that S400 interacts with a set of three
identical binding sites on lysozyme. 相似文献
20.
In this study, two complementary approaches, affinity capillary electrophoresis (ACE) and quantum mechanical density functional theory (DFT) calculations, have been employed for quantitative characterization and structure elucidation of the complex between hexaarylbenzene (HAB)‐based receptor R and lithium ion Li+. First, by means of ACE, the apparent binding constant of Li R + complex (K) in methanol was determined from the dependence of the effective electrophoretic mobilities of Li R + complex on the concentration of lithium ions in the 25 mM Tris/50 mM chloroacetate background electrolyte (BGE) using non‐linear regression analysis. Prior to regression analysis, the effective electrophoretic mobilities of the Li R + complex were corrected to reference temperature 25°C and constant ionic strength 25 mM. The apparent binding constant of the Li R + complex in the above methanolic BGE was evaluated as logK = 1.15±0.09. Second, the most probable structures of nonhydrated Li R + and hydrated Li R +·3H2O complexes were derived by DFT calculations. The optimized structure of the hydrated Li R +·3H2O complex was found to be more realistic than the nonhydrated Li R + complex because of the considerably higher binding energy of Li R +·3H2O complex (500.4 kJ/mol) as compared with Li R + complex (427.5 kJ/mol). 相似文献