Thermal denaturation of α-Lactalbumin in the absence and presence of various concentrations of sucrose, sorbitol, glucose and galactose as sugar osmolytes were measured by monitoring changes in the absorptions that carried out in a Lambd 35 UV-Vis double beam spectrophotometer at pH 6.0. These measurements gave values of Tm (midpoint of denaturation), ∆Hm (enthalpy change at Tm), and ∆Cp (constant-pressure heat capacity change) under a given solvent condition. Using these values of ∆Hm, Tm and ∆Cp , ∆GD o (Gibbs energy change), was determined at a given concentration of each sugar. It has been observed that each sugar stabilizes the α- Lactalbumin in terms of Tm and ∆GD 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 :protein stability, sugar osmolytes, thermal denaturation
ارزش ریالی : 350000 ریال
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