20 research outputs found

    Kinetics and

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    The aqueous degradation of Reactive Yellow 84 (RY84) by potassium peroxydisulfate (K2S2O8) has been studied in laboratory scale experiments. The effect of the initial concentrations of potassium peroxydisulfate and RY84, pH and temperature on RY84 degradation were also examined. Experimental data were analyzed using first and second-order kinetics. The degradation kinetics of RY84 of the potassium peroxydisulfate process followed the second-order reaction kinetics. These rate constants have an extreme values similar to of 9.493 mM−1min−1 at a peroxydisulfate dose of 4 mmol/L. Thermodynamic parameters such as activation (Ea) and Gibbs free energy (ΔG°) were also evaluated. The negative value of ΔGo and Ea shows the spontaneous reaction natural conditions and exothermic nature

    Improvement of Cd<sup>2+</sup> uptake ability of SmtA protein by Lys/Cys mutation; experimental and theoretical studies

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    <div><p>The improved Cd<sup>2+</sup> surface affinity characteristics of a mutated cyanobacterial metallothionein SmtA (K45C) were investigated via experimental and theoretical methods. Molecular dynamics simulations were carried out using a model of Cd<sup>2+</sup> and other ions enclosed in a fully hydrated simulation box with the wild-type or mutated SmtA protein. The theoretical results suggested that mutated SmtA was more powerful in absorption of Cd<sup>2+</sup> than the wild-type protein. Then, the mutated <i>smtA</i> gene (from <i>Synechococcus PCC 7942</i>) was synthesized by simplified gene synthesis method and expressed on isopropyl-beta-d-thiogalactopyranoside induction. The protein expression was investigated by SDS-PAGE and verified by Western blotting. Finally, cadmium uptake ratio of mutant protein toward wild type was analyzed by atomic absorption. This study is the first example of cytoplasmic expression of a mutant protein. Experimental results also verified that the mutation intensifies uptake of Cd<sup>2+</sup> ions.</p></div
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