Chemical denaturation and thermal denaturation of β-lactoglobulin AB in the absence and presence of αS -casein were measured at pH 2.0. It has been observed that ΔGD o , (Gibbs free energy change in absence of denaturant at 25 o C) of β- lgAB: αS –casein ratios 1:1, 1:1.5 and 1:2 is increased. We report that the functional dependence of ΔGD , (Gibbs free energy change) of protein in the absence and the presence of αS -casein concentration is linear. The values of Tm (midpoint of denaturation), ΔHm (enthalpy change at Tm), and ΔCp (constantpressure heat capacity change) under a given solvent condition were measured. It has been observed that each sugar stabilizes the protein in terms of Tm and ΔGD o . The temperature that corresponds to maximum protein stability, TS, is increased in the presence of these osmolytes. The same trend was also observed for TH, the temperature corresponding to zero enthalpy change of denaturation.
کلید واژگان :β-lactoglobulinAB; αS-casein; protein stability; Chemical denaturation; thermal denaturation
ارزش ریالی : 300000 ریال
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