Biochemistry
Nayere Bahamin; Behzad Sareghi
Articles in Press, Accepted Manuscript, Available Online from 19 October 2014
Abstract
In this study, the interaction of various concentrations of Cadmium Sulfate with Peroxidase (E.C 1.11.1.7) was investigated in different temperatures (25-35 °C). For this purpose thermostability, spectrophotometry, spectroflorimetry and kinetics studies were done to obtain thermodynamic parameters including ...
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In this study, the interaction of various concentrations of Cadmium Sulfate with Peroxidase (E.C 1.11.1.7) was investigated in different temperatures (25-35 °C). For this purpose thermostability, spectrophotometry, spectroflorimetry and kinetics studies were done to obtain thermodynamic parameters including ∆G°, ∆H°m, ∆S°m, Tm and also kinetics parameters including Vmax and Km. The results showed that Cadmium Sulfate caused uncompetitive inhibition at different temperatures and increasing of temperature intensified this inhibition effect. Also Cadmium Sulfate was reduced the stability of peroxidase and reduced its Tm. In the spectrophotometric studies the effect of Cadmium Sulfate on the peroxidase in such a way that the absorption in 275nm increased and temperatures increased it too, also the absorption in 404nm (soret bond) decreased and temperature decreased it too. Totally, Cadmium Sulfate ions in a time- and dose- dependent manner and affected by temperature bind to the peroxidase in the heme environment and decrease the thermostability of it, and exert uncompetitive inhibition.
Behzad Shareghi; Maryam Kazemi Nafchi
Volume 6, Issue 4 , June 2018, , Pages 23-33
Abstract
Abstract Peroxidases are a group of oxidoreductases that are produced by a number of microorganisms and plants, and catalyse the reduction of peroxides. Peroxidases are widely used in clinical biochemistry and enzyme immunoassay. Horseradish peroxidase isoenzyme C (HRPC) is one of the characterized peroxidases. ...
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Abstract Peroxidases are a group of oxidoreductases that are produced by a number of microorganisms and plants, and catalyse the reduction of peroxides. Peroxidases are widely used in clinical biochemistry and enzyme immunoassay. Horseradish peroxidase isoenzyme C (HRPC) is one of the characterized peroxidases. The structure of the enzyme is largely alpha helical. Peroxidase enzyme is detox important enzyme that to work process for getting rid of the cells of additional hydrogen peroxide under normal and stress conditions, including contamination with toxic levels of heavy metals, however, severe stress possible influence upon the activity of detoxification enzyme. Kinetics studies of peroxidase enzyme were performed using a spectrophotometer UV-Vis fitted with electronic control system at 35 °C and 45 °C and pH4 and in the presence ferric oxide and copper oxide. Kinetic parameters show that ferric oxide and copper oxide becomes caused the decrease of maximum speed (VMAX) and activity of the enzyme. Likely due to the ferri and copper ions have positively charged, these places are on or near the sites of glycosylation of enzyme and by their negatively charged are suitable binding sites for iron and copper. Likely binding of iron and copper are caused more changes of the secondary structure and makes random coil deduction more than alpha helix.
Behzad Shareghi; Maryam Kazemi Nafchi
Volume 5, Issue 1 , September 2016, , Pages 1-8
Abstract
Abstract Peroxidases are a group of oxidoreductases that are produced by a number of microorganisms and plants, and catalyse the reduction of peroxides. Peroxidases are widely used in clinical biochemistry and enzyme immunoassay. Horseradish peroxidase isoenzyme C (HRP) is one of the characterized peroxidases. ...
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Abstract Peroxidases are a group of oxidoreductases that are produced by a number of microorganisms and plants, and catalyse the reduction of peroxides. Peroxidases are widely used in clinical biochemistry and enzyme immunoassay. Horseradish peroxidase isoenzyme C (HRP) is one of the characterized peroxidases. The structure of the enzyme is largely alpha helical. Kinetics studies of peroxidase enzyme were performed using a spectrophotometer UV-Vis fitted with electronic control system at 35oC and 45oC and pH4 and in the presence ethanol and butanediol. Kinetic parameters show that ethanol and butanediol organic solvents becomes caused the increase of maximum speed (VMAX) and activity of the enzyme. Organic solvents have effect on electrostatic interactions of proteins because their dielectric constant with water is different. In general, reduce properties of polar solvents and decreased dielectric constant becomes caused the increases electrostatic repulsion, leading to the opening of the proteins. Enzymes activity in such organic environments increases stability, activity or facilitate reactions that are difficult to perform in aquatic environments.
Lida Momeni; Sadegh Farhadian; Behzad Shareghi
Volume 4, Issue 4 , May 2016, , Pages 1-9
Abstract
Abstract Adsorption of proteins on inorganic surfaces may lead to structural and functional changes that are dependent on both the nature of the adsorbed proteins and the physicochemical properties of the inorganic surfaces. Chicken egg white lysozyme (E.C 3.2.1.17, MW=14.6 kDa) is a small globular protein, ...
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Abstract Adsorption of proteins on inorganic surfaces may lead to structural and functional changes that are dependent on both the nature of the adsorbed proteins and the physicochemical properties of the inorganic surfaces. Chicken egg white lysozyme (E.C 3.2.1.17, MW=14.6 kDa) is a small globular protein, that consists of 129 amino acid residues with four disulfide bonds. The aim of this study was the survey of the stability and structure of Chicken egg white lysozyme against ZnO nano through thermal stability, fluorescence and spectroscopy and enzyme activity assay in the absence or presence of ZnO nano particle at pH 7.0. The obtained results indicated that thermal stability and activity of lysozyme decreased with increase in ZnO nanoparticles concentration. Moreover, it was observed that ZnO Nano particle quenched the intrinsic fluorescence of lysozyme. The interaction studies of ZnO nanoparticles and lysozyme show that not only water and solvent molecules can effect on 3D structure of lysozyme and protein but also play an important role in adsorption nanoparticles.
B Shareghi; k. Shahdad Nejad
Volume 3, Issue 1 , January 2015, , Pages 7-16
Abstract
Pepsin enzyme is synthesized in the gastric mucosa of vertebrates. Pepsin is composed of 327 amino acid residues, with a molecular mass of 34KD. The structure is predominantly β-strand and random coil with limited α-helix. The two domains are connected via a six-stranded β-sheet plate. ...
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Pepsin enzyme is synthesized in the gastric mucosa of vertebrates. Pepsin is composed of 327 amino acid residues, with a molecular mass of 34KD. The structure is predominantly β-strand and random coil with limited α-helix. The two domains are connected via a six-stranded β-sheet plate. In this study used UV-Vis spectrophotometer pharmacia-4000 with electronic temperature controller system. Thermal stability of porcine pepsin has been investigated in the presence of organic solvents include butanol, ethanol, 1,4-Butanediol and glycerol in different concentrations (0-50% V/V) at pH=2. Tm of pepsin was decreased the presence of butanol, ethanol, 1,4-Butanediol respectively. and Tm of pepsin increased in the presence of glycerol. Also the effects of these organic solvents on the activity of porcine pepsin were studied Activity of pepsin decreased in aqueous butanol, ethanol and 1,4-Butanediol with increasing organic solvent concentration respectively and activity of pepsin increased in presence of glycerol with increasing organic solvent concentration. The changes caused in the catalytic activity by the water-miscible organic solvents include butanol, ethanol and 1,4-Butanediol may be related to structural changes, which were followed by means of thermal stability changes and also change in active site of pepsin. Glycerol also stabilized the structure of pepsin.
