野蚕黑卵蜂寄主识别利它素的纯化及氨基酸组成分析

针对利它素特殊的物理及化学性质 ,采用特定的温度分离方法 ,成功地从野蚕Theophilamandarina和家蚕Bombyxmori的雌蛾性附腺中分别获得了纯度较高的野蚕黑卵蜂Telenomustheophilae寄主识别利它素。对这两种利它素氨基酸组成的分析表明 ,来自家蚕和野蚕雌蛾性附腺的利它素在氨基酸的组成和含量方面非常相似 ,在检测到的 15种氨基酸中 ,甘氨酸、谷氨酸和天冬氨酸的克分子百分数在 10 %以上。从家蚕得到的分别为 2 8 1%、 18 5 %和 12 6 %。从野蚕得到的分别为 2 4 4%、18 1%和 10 1%。这 3种氨基酸之和在家蚕和野蚕中均超过 5 0 %以上。用凝胰乳蛋白酶对这两种利它素进行水解时发现溶液中均产生非水溶性沉淀 ,电泳表明沉淀的多肽蛋白分子量在 10kD左右。这显示在野蚕和家蚕利它素结构中 ,有着与家蚕丝蛋白相类似的结构 ,存在着结晶区域 (沉淀 )和无定形区域 (上清 )。

Fast isolation and amino acids analysis of an egg recognition kairomone of Teleno-mus theophilae from Theophila mandarina and Bombyx mori

Based on the special physical characteristics of an egg recognition kairomone protein of Telenomus theophilae, a simple, practical, and effective technique (temperature approach) was used to purify the kairomone proteins from Bombyx mori and Theophila mandarina. The compositions of amino acids in kairomone proteins of female accessory glands were very similar between the two moths. Molar percentages of glycine, glutamic and aspartic acid of 15 amino acids detected exceeded 10% in both moths: 28.1%, 18.5% and 12.6%, respectively, in B. mori , and 24.4%, 18.1%, and 10.1%, respectively, in T. mandarina. The total amount of these three amino acids exceeded 50% in both moths. Hydrolyzed by chymotrypsin, the polypeptides of the B. mori kairomone protein formed a water-insoluble precipitate. The molecular weight of the polypeptides was about 10 kD as judged by SDS-PAGE. This result suggests that the primary structures of the kairomone protein and silk protein from B. mori are similar, both containing a crystalline (precipitate) and a amorphous (supernatant) region.