蓖麻蚕和家蚕中的谷胱甘肽及正丁基高半胱氨酸亚砜亚胺对它的抑制作用

本文利用乙醛酸排除昆虫中比较高的游离半胱氨酸的干扰,用5,5′-二硫代双(2-硝基苯甲酸)(DTNB)方法测定了蓖麻蚕、家蚕中还原谷胱甘肽的含量及其组织分布,观察到脂肪体、后部丝腺、中肠等均含有非常丰富的谷胱甘肽(GSH),说明谷胱甘肽在昆虫氨基酸的代谢调节控制中起着重要的作用。蓖麻蚕和家蚕中,GSH含量及分布有所区别。五龄中期注射S-正丁基高半胱氨酸亚砜亚胺(BSO)引起家蚕脂肪体GSH含量明显降低,提示蚕γ-谷氨酰半胱氨酸合成酶受RSO强烈抑制;五龄后期,可能由于合成酶活力及GSH周转率均处于较低水平,未观察到GSH含量有明显下降。

GLUTATHIONE IN PHILOSAMIA CYNTHIA AND BOMBYX MORI AND ITS INHIBITION BY BSO

The amounts of reduced glutathione (GSH) and its distribution in different tissues of Philosamia cynthia rieini and Bombyx mori were determined with the DTNB method after removing free cysteine with glyoxylic acid. It was found that large amounts of GSH. were present in the fat,body, silk gland and midgut, suggesting the important role of GSH in the regulation of amino acid metabolism in these two insects. However, the level and distribution of GSH in Philosamia were different from that in Bombyx. During the middle stage of the fifth instar the injection of S-n-biutylhomocystine (BSO) would markedly decrease the level of GSH in Bombyx, presumably due to the inhibition of y-glutamylcysteine synthetase by BSO. But in later fifth instar no decrease, in the amount of GSH was detected because of the lower activity of the y-glutamyleysteine syn-thetase and slow turnover of GSH.