人神经生长因子融合蛋白的纯化及其生物活性的研究

用一株基因工程菌Ｅ．ｃｏｌｉ２４２６／ｐＭＮ表达了麦芽糖结合蛋白－人神经生长因子融合蛋白．菌体超声破碎后，上清液经直链淀粉亲和柱一步即可获ＳＤＳ－ＰＡＧＥ纯融合蛋白（５５ｋＤ），为麦芽糖结合蛋白（４２ｋＤ）与人神经生长因子（１３ｋＤ）的络合物，产率约１０％．产物用鸡胚背根神经节检测生物活性，１ＢＵ不大于１０ｎｇ，与小鼠颌下腺β神经生长因子具有类似生物活性

Purification of Fusion Protein Human Nerve Growth Factor and the Determination of its Biological activity

A fusion protein of maltose binding protein human nerve growth factor was expressed in a gene engineering strain E.coli 2426/pMN. After sonication of cells,the supernatant was purified with an amylose affinity column.The pooled fraction eluted with 20 mmol/L PBS pH 8.0 including 10 mmol/L maltose is a homogeneous protein on the analysis of SDS PAGE.The result of molecular weight estimation showed that it was a complex(55kD) of MBP(42kD) and hNGF(13kD).The yield is about 10%,By the assay of biological activity toward the dorsal root ganglia of chicken embryo,1 biological unit (BU) of the fusion protein is not large than 10 ng.The biological activity of the product ia similar to β NGF from mouse submaxllery.glands.