人胎盘低分子量神经生长因子(hNGF)的分离、纯化和性质鉴定

将从小鼠颌下腺中分离纯化神经生长因子（ＮＧＦ）的方法运用于胎盘，通过中性搅拌抽提，两次ＣＭ－５２阳离子交换层析柱和一次ＳｅｐｈａｄｅｘＧ－７５凝胶过滤得到一纯度和比活都比较高的、可促进神经节生长的碱性蛋白质，通过免疫学（Ｗｅｓｔｅｒｎ－ｂｌｏｔｉｎｇ）和生物学性质（可以促进鸡胚背根神经节长出神经纤维）的鉴定，确定此物是人的一种低分子量的神经生长因子（ｈＮＧＦ）。

ISOLATION,PURIFICATION AND CHARACTERIZATION OF LOW MOLECULAR WEIGHT NGF PROTEIN FROM HUMAN PLACENTA

Nerve growth factor is the first growth factor found and studied.It is one of the most important growth factors of the nervous system.It was found by Mr.Bucker in 1948 and isolated by Ms.Leiv Montalcini from adult male mouse submaxillary gland.It isnot only necessary for the developing and maintaining of normal function of epithelial and central nervous systems,but also can influence the immune,blooding and reproductive systems. An active protein has been purified from human placenta by the same way of isolating NGF from adult male mouse submaxillary gland through neutral extraction,two CM 52 ion exchange chromatorgraphy,acidified precipitation and a Sephadex G 75 gel filtration.The molecular weight of this new protein is approximately 15 000 indicated by SDS PAGE.The pI of it is 9.1 on isoelectric focusing electrophoresis.This protein can specifically stimulate the neutrite fiber outgrowth from chicken dorsal root ganglia.It has a positive result by Western blotting,so we named it the human low molecular weight Nerve Growth Factor(hNGF). As the NGF amount of the adult male mouse submaxillary gland is relatively high,it is the most common material used to isolate NGF.To avoid harmful affects from heterogeneous proteins and viruses,we isolate the NGF from human placenta.Because the amounts of NGF in human tissues are very limited and the composition of placenta is so complicated,the NGF purity of the final product is not very high.But the specific activity has amounted to 50 000U/mg which could satisfy demands of production. The procedure of isolation and purification in our experiments is simple and convenient and the source of raw material placenta is plentiful,so it is suitable for scale production.