沙冬青叶片热稳定抗冻蛋白特性分析

Biological Characterization of Heat_stable Antifreeze Proteins from Leaves of Ammopiptanthus mongolicus 

用双向电泳电泳回收法从沙冬青（ Ａｍｍｏｐｉｐｔａｎｔｈｕｓ ｍｏｎｇｏｌｉｃｕｓ（Ｍａｘｉｍ ．） Ｃｈｅｎｇｆ．） 叶片热稳定蛋白质中分离到一种抗冻蛋白ａｆｐ，其分子量为４０ ｋＤ，ｐＩ为９．０ ，热滞活性为０ ．９ ℃（２０ ｍｇ／ｍＬ） ，和其他抗冻蛋白进行比较，没有发现相同的类型。ａｆｐ Ｎ 端序列为ＳＤＤＬＳＦＴＦＮＫＦＶＰＣＱＴＤＩＬＦ。ａｆｐ 在沙冬青体内广泛分布且叶片含量较高，可能是沙冬青抗冻生理过程中的主要物质，对于沙冬青抵御冬季冷冻温度具有重要的作用。

Antifreeze protein(afp) was purified from the heat stable proteins in the leaves of Ammopiptanthus mongolicus (Maxim.) Cheng f. by two_dimensional electrophoresis_electrophoretic elution. Its molecular weight and pI are about 40 kD and 9.0 respectively, and its thermal hysteresis activity (THA) is 0.9 ℃ at 20 g/L. afp is different from other antifreeze proteins. The N_terminal 20 amino acids of afp is SDDLSFTFNKFVPCQTDILF. afp is abundant in leaves and may play an important role in the antifreeze process in A. mongolicus during the period of overwintering.