等电聚焦法测定2.5S NGF的等电点

Detection of isoelectric point of 2.5 S nerve growth factor by isoelectrofocusing

采用水平等电聚焦法测定了２５Ｓｍ神经生长因子（ＮＧＦ）的等电点。经测定，纯化的２５ＳｍＮＧＦ的等电聚焦为三条带，这与文献报道相一致，等电点ｐＨ值分别为ｐＨ８７、９０、９３，其主要成分为β亚基ＮＧＦ及其修饰物的混合物，包括在羧基端失去８个氨基酸残基和在氨基端失去１个精氨酸残基，由这三种组分构成的ＮＧＦ统称为２５ＳｍＮＧＦ。

The isoelectric point of nerve growth factor was detected by flat isoelectro focusing assay,three isoelectric phoresis stripes were obtained and their isoelectric point were pH 8.7,pH9.0 and pH9.3 respectively.The results showed the NGF were consisted of the mixture of β subunit and modified NGF components.one of the modified NGF was 8 amino acid residue lost in carboxy1 terminal,the other was arginine lost in amino terminal.All of them are consisted of 2.5 Sm NGF.