眼镜蛇膜毒素对菠菜叶绿体光合膜的影响

EFFECT OF CARDIOTOXIN FROM THE VENOM OF NAJA NAJA ATRA ON THE PHOTOSYNTHETIC MEMBRANE OF SPINACH CHLOROPLASTS.

眼镜蛇(Naja naja atra)蛇毒经柱层析分离,得到15个蛋白组份。观察不同组份蛋白对菠菜体叶绿体的功能和形态结构影响。磷脂酶A组份对光合电子传递只起抑制作用,膜毒素组份对光合电子传递呈现促进作用。膜毒素使光合磷酸化解联,ADP/O比值和光合控制比值下降,光诱导的叶绿体pH变化受抑制,以及叶绿体延迟发光所反映的类囊体膜电位和质子梯度消失。研究证明,蛇毒对叶绿体的作用,主要是磷脂酶A和膜毒素两个组份复合影响的结果。

Spinach chloroplasts were treated by incubation with phospholipase A or with cardiotoxin fractionated from Naja Naja venom.It was shown that the activity of Hill reaction with methylviologen as an electron acceptor was inhibited by phospholipase A,However,this activity was distinctly stimulated by cardiotoxin.Cardiotoxin lowcrd the ADP/O ratio,photosynthetic control,light-induced H+transport and delayed light emission of spinach chloroplasts.They were usually taken as indicaters of energy-transducing functions of chloroplasts.The chloroplasts treated with cardiotoxin were also examined under electron microscope.It was found that the lameller membranes of grama were swollen up and a lot of alveolus could be seen in stroma during incubation.