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RETRACTED ARTICLE: Study of stabilities of L-cysteine and L-methionine with divalent metal ions: A comparison of thermodynamic data
, Article 5th International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2011 ; 2011 ; 9781424450893 (ISBN) ; Sharif University of Technology
Abstract
The acidity and stability constants of M-Met (M: M2+; Met 1: L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation with L-cysteine (Cys). It is shown that regarding to M ion - binding properties vital differences on complex bilding were considered. It is demonstrated, that in M-Met complexes, M ion is coordinated to the carboxyl group, M ion is also able to build macrochelate over amine group. The upmentioned results demonstrate that for M-Met complex the stability constants is also largly determined by the affinity of Cu2+ for amino group but in opposite to Met, some metal ions such as Co2+, Cu2+, and Zn2+ build with Cys 2...
Effect of Cysteine Substitutions on the Structural and Magnetic Properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine Nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; 2018 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini, H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2018
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Effect of cysteine substitutions on the structural and magnetic properties of Fe3O4–Cysteine/RGO and Fe3O4/RGO–Cysteine nanocomposites
, Article Journal of Superconductivity and Novel Magnetism ; Volume 32, Issue 5 , 2019 , Pages 1299-1306 ; 15571939 (ISSN) ; Mehrani, K ; Madaah Hosseini , H. R ; Zare, K ; Sharif University of Technology
Springer New York LLC
2019
Abstract
We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of...
Radial basis function-artificial neural network (RBF-ANN) for simultaneous fluorescent determination of cysteine enantiomers in mixtures
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 261 , 2021 ; 13861425 (ISSN) ; Reza Hormozi Nezhad, M ; Abdollahi, H ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The determination of chiral compounds is critically important in chemical and pharmaceutical sciences. Cysteine amino acid is one of the important chiral compounds where each enantiomer (L and D) has different effects on fundamental physiological processes. The unique optical properties of nanoparticles make them a suitable probe for the determination of different analytes. In this work, the water-soluble thioglycolic acid (TGA)-capped cadmium-telluride (CdTe) quantum dots (QDs) were applied as optical nanoprobe for the simultaneous determination of cysteine enantiomers. The difference in the kinetics of the interactions between L- and D-cysteine with CdTe QDs is used for multivariate...
Effective surface modification of MnFe2O4@SiO2@PMIDA magnetic nanoparticles for rapid and high-density antibody immobilization
, Article Applied Surface Science ; Volume 426 , 2017 , Pages 1023-1029 ; 01694332 (ISSN) ; Soleimani, M ; Ghahremanzadeh, R ; Vossoughi, M ; Esmaeili, E ; Sharif University of Technology
Abstract
The present study is aimed at the synthesis of MnFe2O4@SiO2@PMIDA in terms of highly efficient sensing platform for anti-prostate specific membrane antigen (PSMA) immobilization. Superparamagnetic manganese ferrite nanoparticles were synthesized following co-precipitation method and then SiO2 shell was coated on the magnetic core with tetraethyl orthosilicate (TEOS) through a silanization reaction to prevent oxidation, agglomeration and, increase the density of OH groups on the surface of MnFe2O4. Subsequently, MnFe2O4@SiO2@PMIDA obtained as a result of the reaction between N-(phosphonomethyl)iminodiacetic acid (PMIDA) and MnFe2O4@SiO2. The reactive carboxyl groups on the surface of magnetic...
Conservation of statistical results under the reduction of pair-contact interactions to solvation interactions
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 72, Issue 6 , 2005 ; 15393755 (ISSN) ; Farzami, R. R ; Ejtehadi, M. R ; Sharif University of Technology
2005
Abstract
We show that the hydrophobicity of sequences is the leading term in Miyazawa-Jernigan interactions. Being the source of additive (solvation) terms in pair-contact interactions, they were used to reduce the energy parameters while resulting in a clear vector manipulation of energy. The reduced (additive) potential performs considerably successful in predicting the statistical properties of arbitrary structures. The evaluated designabilities of the structures by both models are highly correlated. Suggesting geometrically nondegenerate vectors (structures) as proteinlike structures, the additive model is a powerful tool for protein design. Moreover, a crossing point in the log-linear diagram of...
Useful multivariate kinetic analysis: Size determination based on cystein-induced aggregation of gold nanoparticles
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 115 , 2013 , Pages 588-594 ; 13861425 (ISSN) ; Nezhad, M. R. H ; Abdollahi, H ; Sharif University of Technology
2013
Abstract
This study describes spectrometric monitored kinetic processes to determine the size of citrate-capped Au nanoparticles (Au NPs) based on aggregation induced by L-cysteine (L-Cys) as a molecular linker. The Au NPs association process is thoroughly dependent on pH, concentration and size of nanoparticles. Size dependency of aggregation inspirits to determine the average diameters of Au NPs. For this aim the procedure is achieved in aqueous medium at pH 7 (phosphate buffer), and multivariate data including kinetic spectra of Au NPs are collected during aggregation process. Subsequently partial least squares (PLS) modeling is carried out analyzing the obtained data. The model is built on the...
Modeling of aqueous biomolecules using a new free-volume group contribution model
, Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 8 , 2009 , Pages 4109-4118 ; 08885885 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Sharif University of Technology
2009
Abstract
In this article, a new group contribution model is suggested for obtaining the thermodynamic properties of biomolecules in aqueous solutions. Accordingly, a Freed-FV model has been applied for the combinatorial free-volume term. The activity coefficients, solubilities, densities, and vapor pressures of amino acids and simple peptides in aqueous solutions were correlated, using the proposed group contribution model. Group interaction parameters of the proposed model were obtained by use of experimental data from amino acids available in the literature. The results demonstrate that the group contribution model can accurately correlate activity coefficient, solubility, density, and vapor...
Correlation and prediction the activity coefficients and solubility of amino acids and simple peptide in aqueous solution using the modified local composition model
, Article Fluid Phase Equilibria ; Volume 255, Issue 2 , 2007 , Pages 160-166 ; 03783812 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Sharif University of Technology
2007
Abstract
In this work, the modified Wilson model was used to obtain the activity coefficients of amino acids and simple peptides in non-electrolyte aqueous solutions. The Wilson model was modified using the new local mole fraction proposed by Zhao et al. and non-random case for the reference state. The binary interaction parameters (BIP) of the modified Wilson model for amino acid-water pairs were obtained using the experimental data of the activity coefficients for amino acids available in the literature. The modified Wilson model was also used to correlate the solubility of amino acids in water and the values of Δh/R, Δs/R, and Δg/R of the solutions studied were reported. The results obtained...
Protein folding rates correlate with heterogeneity of folding mechanism
, Article Physical Review Letters ; Volume 93, Issue 20 , 2004 , Pages 208105-1-208105-4 ; 00319007 (ISSN) ; Ejtehadi, M. R ; Plotkin, S. S ; Sharif University of Technology
American Physical Society
2004
Abstract
The folding rates of protein were shown to correlate with the degree of heterogeneity in the formation of native contacts. It was shown that both experimental rates and simulated free energy barriers for 2-state proteins depend on the degree of heterogeneity present in the folding process. Heterogeneity due to variance in the distribution of native loop lengths, and variance in the distribution of φ values, were observed to increase folding rates and reduce folding barriers. The observed effect due to φ variance was found to be the most statistically significant, because φ variance captures both heterogeneity arising from native topology and that arising from energetics
NMR spectroscopy-based metabolomic study of serum in sulfur mustard exposed patients with lung disease
, Article Biomarkers ; Volume 22, Issue 5 , 2017 , Pages 413-419 ; 1354750X (ISSN) ; Arefi Oskouie, A ; Rezaei Tavirani, M ; Aliannejad, R ; Taheri, S ; Fathi, F ; Naseri, M. T ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
Sulfur mustard (SM) is a vesication chemical warfare agent for which there is currently no antidote. Despite years of research, there is no common consensus about the pathophysiological basis of chronic pulmonary disease caused by this chemical warfare agent. In this study, we combined chemometric techniques with nuclear magnetic resonance (NMR) spectroscopy to explore the metabolic profile of sera from SM-exposed patients. A total of 29 serum samples obtained from 17 SM-injured patients, and 12 healthy controls were analyzed by Random Forest. Increased concentrations of seven amino acids, glycerol, dimethylamine, ketone bodies, lactate, acetate, citrulline and creatine together with the...
NMR- and GC/MS-based metabolomics of sulfur mustard exposed individuals: a pilot study
, Article Biomarkers ; Volume 21, Issue 6 , 2016 , Pages 479-489 ; 1354750X (ISSN) ; Aliannejad, R ; Rezaei Tavirani, M ; Arefi Oskouie, A ; Naseri, M. T ; Parastar, H ; Aliakbarzadeh, G ; Fathi, F ; Taheri, S ; Sharif University of Technology
Taylor and Francis Ltd
Abstract
Sulfur Mustard (SM) is a potent alkylating agent and its effects on cells and tissues are varied and complex. Due to limitations in the diagnostics of sulfur mustard exposed individuals (SMEIs) by noninvasive approaches, there is a great necessity to develop novel techniques and biomarkers for this condition. We present here the first nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC/MS) metabolic profiling of serum from and healthy controls to identify novel biomarkers in blood serum for better diagnostics. Of note, SMEIs were exposed to SM 30 years ago and that differences between two groups could still be found. Pathways in which differences between SMEIs and...
Oxido-peroxido W(VI)-histidine–MgAl-layered double hydroxide composite as an efficient catalyst in sulfide oxidation
, Article Applied Organometallic Chemistry ; Volume 32, Issue 6 , 2018 ; 02682605 (ISSN) ; Amini, M ; Morteza, S ; Farnia, F ; Bayrami, A ; Bagherzadeh, M ; Gautam, S ; Chae, K. H ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
Oxido-peroxido W(VI)-histidine–MgAl-layered double hydroxide composite was prepared by using MgAl-layered double hydroxide as a host and oxido-peroxido W(VI)-histidine complex as a guest. The composite was characterized by XRD, IR, EDX,SEM and TEM techniques. This composite is tested for catalytic selective sulfoxidation reactions using hydrogen peroxide as oxidant showing good to moderate conversion along with high selectivity. Copyright © 2018 John Wiley & Sons, Ltd
Experimental investigation and thermodynamic modeling of amino acids partitioning in a water/ionic liquid system
, Article Journal of Molecular Liquids ; Volume 260 , 15 June , 2018 , Pages 386-390 ; 01677322 (ISSN) ; Ghotbi, C ; Habibi Zare, M ; Shirazian, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Amino acids partitioning including phenylalanine, glutamic acid, and tryptophan in aqueous and ionic liquid phases at temperature of 298.15 K and atmospheric pressure were measured. 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide used in this work can produce two phases with water immediately. The effect of aqueous solution pH on amino acids partitioning was studied and revealed that amino acid partitioning coefficient was decreased with increasing pH. This phenomenon pertains to the electrostatic interaction between cations of amino acid and the anions of ionic liquid which is decreased when pH increases. Considering the effect of pH, liquid-liquid equilibrium data of amino...
A new model for predicting activity coefficients in aqueous solutions of amino acids and peptides
, Article Journal of Chemical Thermodynamics ; Volume 35, Issue 1 , 2003 , Pages 101-112 ; 00219614 (ISSN) ; Ghotbi, C ; Taghikhani, V ; Sharif University of Technology
2003
Abstract
A new two-parameter model based on the perturbation of a hard-sphere reference has been developed to correlate the activity coefficients of several amino acids and simple peptides in aqueous solutions. The hard-sphere equation of state used as the reference in the model was proposed recently by Ghotbi and Vera. The perturbation terms coupled with the reference hard-sphere equation of state are attributed to the dispersion forces and the dipole-dipole interactions. The Lennard-Jones and Keesom potential functions are used to represent the dispersion and dipole-dipole interactions, respectively. The results of the new model are compared with those obtained by other models. It is shown that the...
Synthesis, X-ray structure and ascorbic oxidation properties of ternary α-amino acid Schiff base-bipy Cu(II) complexes as functional models for ascorbic oxidase
, Article Polyhedron ; Volume 53 , 2013 , Pages 76-82 ; 02775387 (ISSN) ; Amini, Z ; Boghaei, D. M ; Notash, B ; Sharif University of Technology
2013
Abstract
Three ternary copper(II) complexes [Cu(5-bromo-salTyr)(bipy)]·1/ 2CH3OH (1), [Cu(5-bromo-salLue)(bipy)]·CH3OH (2) and [Cu(5-bromo-salTrp)(bipy)]·3CH3OH (3) (where 5-bromo-salTyr, 5-bromo-salLue and 5-bromo-salTrp are tridentate Schiff base ligands derived from the condensation of 5-bromosalicylaldehyde with tyrosine, leucine and tryptophan, respectively, and bipy is 2,2′-bipyridine) have been prepared and characterized by elemental analysis, electronic, IR spectroscopies, magnetic measurement and cyclic voltammetry. The complexes, 1 and 3 have been also structurally characterized by X-ray diffraction technique. Crystal structures of 1 and 3 complexes displayed a distorted square-pyramidal...
Synthesis of high surface area nanocrystalline anatase-TiO2 powders derived from particulate sol-gel route by tailoring processing parameters
, Article Journal of Sol-Gel Science and Technology ; Volume 40, Issue 1 , 2006 , Pages 15-23 ; 09280707 (ISSN) ; Cordero Cabrera, M. C ; Ghorbani, M ; Fray, D.J ; Sharif University of Technology
2006
Abstract
Stabilised titania sols were prepared using an additive free particulate sol-gel route, via electrostatic stabilisation mechanism, with various processing parameters. Peptisation temperature, 50°C and 70°C, and TiO2 concentration, 0.1, 0.2 and 0.4 molar, were chosen as processing parameters during sol preparation. Results from TiO2 particle size and zeta potential of sols revealed that the smallest titania hydrodynamic diameter (13 nm) and the highest zeta potential (47.7 mV) were obtained for the sol produced at the lower peptisation temperature of 50°C and lower TiO 2 concentration of 0.1 M. On the other hand, between the sols prepared at 70°C, smaller titania particles (20 nm) and higher...
Study and optimization of amino acid extraction by emulsion liquid membrane
, Article Separation Science and Technology ; Volume 43, Issue 11-12 , 2008 , Pages 3075-3096 ; 01496395 (ISSN) ; Alemzadeh, I ; Vossoughi, M ; Sharif University of Technology
2008
Abstract
A batch extraction of an essential amino acid, phenylalanine, from an aqueous solution of different concentrations by an Emulsion Liquid Membrane (ELM) was developed using D2EHPA as a cationic carrier, Span 80 as the surfactant, paraffin, and kerosene as the diluents, and HCl as the internal electrolyte. All effective parameters such as the initial pH of the aqueous external phase, the electrolyte concentration in the aqueous internal phase, carrier, and surfactant concentration in the emulsion, the volume ratio of the organic to aqueous internal phase (Roi), the volume ratio of the W/O emulsion to the aqueous external phase (Rew) and time were examined and optimized using the Taguchi...
Study and optimization of Amino Acid Extraction by emulsion Liquid Membrane
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Vosoughi, M ; Alemzadeh, I ; Hexion Specialty Chemicals; Mitsubishi Chemical Corporation; CS Cabot; Zentiva; BorsodChem MCHZ ; Sharif University of Technology
2006
Abstract
A batch extraction of an essential amino acid, Phenylalanine, from an aqueous solution of different concentrations by an Emulsion Liquid Membrane (ELM) was developed using D2EHPA as a cationic carrier, Span 80 as the surfactant, paraffin and kerosene as the diluents, and HCl as the internal electrolyte. All effective parameters such as pH of initial aqueous external phase, electrolyte concentration in aqueous internal phase, carrier and surfactant concentration in emulsion, volume ratio of the organic to aqueous internal phase (Roi), volume ratio of the W/O emulsion to aqueous external phase (Rew) and time were examined and optimized using Taguchi method which was the first time of...
Failure tolerance of motif structure in biological networks
, Article PLoS ONE ; Volume 6, Issue 5 , May , 2011 ; 19326203 (ISSN) ; Jalili, M ; Sharif University of Technology
2011
Abstract
Complex networks serve as generic models for many biological systems that have been shown to share a number of common structural properties such as power-law degree distribution and small-worldness. Real-world networks are composed of building blocks called motifs that are indeed specific subgraphs of (usually) small number of nodes. Network motifs are important in the functionality of complex networks, and the role of some motifs such as feed-forward loop in many biological networks has been heavily studied. On the other hand, many biological networks have shown some degrees of robustness in terms of their efficiency and connectedness against failures in their components. In this paper we...