木菠萝凝集素的纯化与性质研究

Purification and Property of Lectins from the Jack Fruit (Artocarpus heterophyllus)

木菠萝种子经抽提、４０％～６０％饱和度硫酸铵沉淀和Ｇａｌ－Ｓｅｐｈａｒｏｓｅ６Ｂ亲和层析，得到纯化的木菠萝凝集素（Ｊａｃａｌｉｎ）。Ｊａｃａｌｉｎ分子量约为５８２００，由分子量分别是１４０００和１５８００的亚基组成，等电聚焦电泳显示多条区带，其ｐＩ为５．７～８．６５，Ｓｃｈｉｆｆ＇ｓ试剂染色证明它是一种糖蛋白，Ｎ－末端为精氨酸和甘氨酸。Ｊａｃａｌｉｎ能凝集除山羊、鸡以外的多种动物和人Ａ、Ｂ、Ｏ和ＡＢ血型红细胞，凝集活性受Ｎ－酰凝半乳糖胺（ＧａｌＮＡｃ）和半乳糖（Ｇａｌ）抑制。在ｐＨ值为４．５～１０，ｐＨ改变不影响Ｊａｃａｌｉｎ凝集活性。

The lectin of Jack Fruit (Jacalin) was isolated and purified from the seeds of the Jack Fruit by precipitate of 40%￣60% saturation ammonium sulfate and affinity chromatography on Gal-Sepharose 6B. Jacalin had an apparent molecular weight of about 58 200 and is composed of two kinds of subunits which had molecular weight 14 000 and 15 800, respectively. Isoelectric focusing on polyacrylamide gel showed that Jacalin gave a spread of components with calculated isoelectric point between 5.7 and 8.65. Jacalin is a glycoprotein by assay of Schiff's stain. The two N-terminals are argenine and glynine. Jacalin could agglutinate red blood cells.