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Tsereteli G. I. Belopolskaya T. V. Grunina N. A. Vaveliouk O. L. 《Journal of Thermal Analysis and Calorimetry》2000,62(1):89-99
By method of differential scanning calorimetry the absolute values of heat capacity for the systemwater–biopolymer (globular
and fibrillar proteins and DNA) were measured in a wide range of temperatures (from -30 up to 130°C) and concentrations of
proteins both in native and denatured states. Thermal properties of humid denatured biopolymers demonstrate a characteristic
anomaly in the form of the heat capacity jump at temperature depending on the bound water content. It has been shown that
in the systems studied a glass transition, where water serves as a native plasticizer, is observed. It has been established
that the S-shaped character of all heat capacity curves obtained on dehydration for native and denatured biopolymers is due
to the gradual transition to the glassy state of both native and denatured samples. It was found that thermally denatured
humid small globular proteins at subsequent dissolving in water at room temperature are able to restore their native structure.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Belopolskaya T. V. Tsereteli G. I. Grunina N. A. Vaveliouk O. L. 《Journal of Thermal Analysis and Calorimetry》2000,62(1):75-88
The temperature dependences of heat capacity for water–denaturated biopolymer (globular proteins, collagen and DNA) were measured
in a wide range of temperatures (0–140°C) and water content of the systems. It has been shown that thermally denaturated globular
proteins (lysozyme, myoglobin and catalase) are able to form the thermoreversible heat-set structures under the certain conditions
studied. The additional endothermal maximum observed is the calorimetric manifestation of the phase transition related to
the melting of these thermotropic non-native structures. The melting gels are completely formed just after denaturation during
relatively short time and only their prolonged state at T>T
d leads to their transformation to thermoirreversible non-melting ones. The post denaturated structures from water-denaturated
protein (Mb, Lys and RN-ase) systems with a different amount of free water were also studied. The thermoreversible cold-set
gels are formed from both water-denaturated DNA and water-denaturated collagen systems. These thermotropic structures are
metastable. A spatial gel network of both collagen and DNA is formed from the native-like renaturated structures.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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