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, ...
Read More
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. ...
Read More
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.
