凤凰木种子蛋白的分离提纯和生化性质  

Isolation,Characterization and Secondary Structure Content Prediction of Novel Proteins from the Seeds of Delonix regia

作　　者：王文忠[1] 潘克桢[1] 

机构地区：[1]中国科学院福建物质结构研究所

出　　处：《生物化学杂志》1995年第3期270-275,共6页

摘　　要：研究了植物凤凰木种子中的蛋白质成分，试图分离出新的核糖体失活蛋白凤凰木种子经磷酸盐缓冲液抽提，硫酸铵分级盐析，分子筛和阴离子交换剂等多次柱层析，分离出三种组分ＤｒⅠ、ＤｒⅡ和ＤｒⅢ．ＳＤＳ－ＰＡＧＥ和ＩＥＦ实验表明这三种蛋白质均达到单一纯，而ＨＰＬＣ实验则表明它们的纯度不低于９０％。它们的分子量据ＳＤＳ－ＰＡＧＥ和ＨＰＬＣ实验分别约２３５００、２６０００、２８５００．ＩＥＦ实验测得三者的等电点均为５．２左右。测定了组分ＤｒⅠ的蛙卵泡裂解活性，其毒性约为天花粉蛋白的１／４０．分析了它们的氨基酸组成。估算了三种蛋白质的二级结构含量，结果表明三者均富含β折叠结构。已有的实验事实表明这三种蛋白质的生化行为明显异于核糖体失活蛋白，因而很可能不属于这一蛋白质家族。in an attempt to search for novel ribosome inactivating proteins(RIPs),the protein constituents of the seeds of the plant Delonix regia have been investigated. Three novel proteins ,Dr Ⅰ,Dr Ⅱ,and Dr Ⅲ,have been isolated and purified to homogeneity as demonstrated by SDSPAGE and IEF experiments. The degrees of purity of all the three proteins exceed 90% as estimated by HPLC analysis. The molecular masses of the three proteins are approximately 24kD,26kD and 29kD respectively by both SDS-PAGE and HPLC analyses. The isoelectric points were estimated to be around PHS. 2 by IEF experiment. The protein Dr Ⅰ has also been assayed for GVBD activity and showed approximately 1/40 as effective as trichosanthin.The amino acid compositions have also been determined.Secondary structure content estimations reveal that the three proteins are all abundant in β-sheet structure. The biochemical behavior of the three proteins resembles each other and differs from that of RIP family. Taking all the evidences available, the proteins most probably belong to a distinct protein family other than the RIP family.

关 键 词：凤凰木 种子蛋白 分离 提纯 

分 类 号：Q949.406[生物学—植物学]