Abstract: Antifreeze proteins (AFPs) , because of their ability of adsorbing onto the surface of ice crystals and modifying their growth , have been found in many different organisms that are exposed to chilling and freezing temperatures . It is very important to increase the resisting and coercing ability at low temperature . DE-52 ion- exchange cellulose was used to extract and separate the antifreeze proteins from Ammopiptanthus nanus leaves. Differential scanning calorimetry (DSC) was used to measure the thermal hysteresis activity (THA) . The results reveal that when the concentration of the protein is 20mg/ml , the THA of the AFPs is 0 . 46℃ . Its molecular weight is about 119. 24 kDa by sodium dodecyl sulfate polyacrylam ide gel electrophoresis (SDS-PAGE) .

Key words: Ammopiptanthus nanus