人血浆MBL的分离纯化及其特性鉴定

ISOLATION AND CHARACTERIZATION OF MANNANBINDING LECTIN FROM HUMAN PLASMA

应用甘露聚糖－Ｓｅｐｈａｒｏｓｅ４Ｂ柱亲和层析，从人血浆中分离纯化了甘露聚糖结合凝集素（ＭＢＬ）。在还原条件下进行ＳＤＳ－ＰＡＧＥ，该结合蛋白显示２９ＫＤ的单一条带。１２５Ｉ－甘露聚糖与ＭＢＬ的结合是浓度依赖、可饱和的，且受Ｎ－乙酰甘露糖胺、Ｎ－乙酰葡糖胺、甘露糖及Ｌ－岩藻糖的抑制，但葡萄糖、半乳糖及其它单糖则否。这种结合依赖Ｃａ２＋，达５０％最大结合量的Ｃａ２＋浓度大约为１ｍｍｏｌ／Ｌ。

Mannanbinding lectin(MBL)was isolated from human plasma by affinity chromatography on mannanSepharose 4B.It appears as a single band with an apparentmolecular weight of 29 000 on SDSPAGE under reducing conditions.Binding of 125Imannan to MBL is concentrationdependent,saturable and inhibited by Nacetylmannosamine,Nacetylglucosamine,mannose,or Lfucose but not by glucose,galactose,or other sugars.125Imannan binding to MBL is Ca2+dependent,with 50% of maximal binding at approximately 1mmol/L CaCl2.