丝瓜籽中蛋白质生物合成抑制蛋白的分离、纯化及性质研究  

Isolation and Characterization of Protein-Biosynthesis Inhibiting Proteins from Seeds of Luffa cylindrica

作　　者：高闻达[1] 曹惠婷 季瑞华[1] 张祖传[1] 

机构地区：[1]中国科学院上海生物化学研究所

出　　处：《生物化学与生物物理学报》1994年第3期289-295,共7页

基　　金：国家863高科技项目

摘　　要：丝瓜（Ｌｕｆｆａｃｙｌｉｎｄｒｉｃａ）种籽，经捣碎、抽提、硫酸铵分级沉淀，ＣＭ－５２离子交换层析，Ｓｅｐｈａｃｒｙ１Ｓ－１００分子筛，阳离子交换ＦＰＬＣ等步骤，分离到两种单链蛋白质生物合成抑制蛋白：Ｌｕｆｆｉｎ－Ａ和Ｌｕｆｆｉｎ－Ｂ。它们都是等电点接近１０的碱性蛋白，ＳＤＳ－ＰＡＧＥ测定分子量分别约为２７ｋｄ和２８ｋｄ，氨基酸组成分析表明两者具很大同源性，但免疫双扩散及ＥＬＩＳＡ检测证明两者的免疫原性有差异。Ｌｕｆｆｉｎｓ对兔网织红细胞裂解液的蛋白质生物合成有强烈的抑制作用，ＩＣ５０分别为１．４×１０－１１ｍｏｌ／Ｌ和２．０×１０－１１ｍｏｌ／Ｌ，比ＴＣＳ的２．９×１０－１０ｍｏｌ／Ｌ低得多。因而，Ｌｕｆｆｉｎｓ很有可能成为肿瘤导向药物的高效＂弹头＂。Two single chain protein-biosynthesis inhibiting Proteins: Luffin-A and B were isolated from the seeds of Luffa cylindrica. Luffins were extracted from defatted meal of the seeds at PH 7.2, fractioned by ammonium sulfate precipitation, and then aPPlied to CM-52 ion-exchange chromatography. SephacrylS-100 gel filtration and ion-exchange FPLC. Luffin-A. B are basic proteins with isoeleetric points of about 10 with molecular weights of 27kd and 28kd respectively.Although their amino acid compositions Showed them to be homogeneous Proteins,their immunogenities as judged by double-diffusion and ELISA indicated some difference. Luffins exhibit potent inhibition of protein synthesis in rabbit reticulocyte lysate. IC50 are 1 .4×10-11 M and 2 .0×10-11 M respectively, which are muchlower than that of TCS (2.9×10-10M), It is promising that Luffins may be used asan efficient toxin moeity of immunotoxins.

关 键 词：丝瓜 种子 蛋白 生物合成 抑制蛋白 

分 类 号：S642.401[农业科学—蔬菜学]