牛生长激素结构不均一性的研究

Study on the Molecular Size Heterogeneity of Bovine Growth Hormone

本文报导用常规方法分离纯化的牛生长激素,在还原性SDS-11％聚丙烯酰胺凝胶电泳中呈分子量很接近的两条主带(22KD,21.5KD)。用单克隆抗体和多克隆抗体亲和层析技术分析了不同分子量形式的牛生长激素的转化,结果表明:牛生长激素可能在pH5.5条件下转化为21.5KD分子,在pH8.3条件下则转化18KD分子。这几种形式的牛生长激素均保留与抗体的结合力,但亲和力不尽相同,如在亲和层析的洗脱性质上存在差异。已检验分离并部分纯化了18KD分子以备作进一步的研究。

Bovine growth hormone(bGH) purified by neutral extraction and Sepha-dex G-100 chromatography exhibits two major bands by SDS-PAGE analysis. Monoclonal antibody and polyclonal antibody were employed to analyse molecular size heterogeneity of bGH. It was found that bGH can be converted into a 21.5KD molecular form at pH5.5 and a 18KD molecular form at pH8.3. All three forms retain their affinity to the antibodies. But the affinity of the 18KD form is different from other forms and it exhibits different elution time when it was eluted from immunoadsorbent. Using affinity chromatography, we have separated and partially purified the 18KD form of bGH for further study.