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  • 1 Peking University Institute of Physical Chemistry Beijing 100871 P. R. China
  • 2 Chinese Academy of Sciences Institute of Developmental Biology Beijing 100080 P. R. China
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Abstract  

Antifreeze protein (AFP) can lower the freezing point by inhibiting the growth of ice crystals. In this article, the thermal hysteresis activity (THA) of a plant AFP was measured with differential scanning calorimetry (DSC). As is shown, when the amount of ice in the sample was less than 5% THA of this AFP reached as high as 0.35°C. The secondary structure of this AFP was studied with circular dichroism (CD). The CD spectrum from 195to 240 nm indicated a well-defined secondary structure consisting 11% α-helix, 34%antiparallel β-sheet and 55% random coil.