Vilella E, Bengtsson-Olivecrona G, Stigbrand T, Jensen P E
Center of Biomedical Research, Hospital de Sant Joan, Reus, Spain.
Biochem J. 1994 Jun 1;300 ( Pt 2)(Pt 2):443-8. doi: 10.1042/bj3000443.
The interaction between bovine lipoprotein lipase (bLPL) and human alpha 2-macroglobulin (alpha 2M) was studied by use of non-denaturing PAGE and gel-permeation, Zn(2+)-Sepharose and heparin-Sepharose chromatography. It was demonstrated that bLPL in vitro binds non-covalently to native alpha 2M, but not to the receptor-recognized form produced by treatment of alpha 2M with chymotrypsin or methylamine. A small amount of bLPL was bound covalently to alpha 2M by disulphide interchange, when incubated together with chymotrypsin or methylamine. Whereas alpha 2M in complex with bLPL still bound to Zn(2+)-Sepharose, bLPL lost the ability to bind to heparin-Sepharose. Preincubation of bLPL with heparin prevented complex-formation with alpha 2M, suggesting that alpha 2M interacts with the heparin-binding domain of bLPL. Experiments in which 125I-bLPL was incubated with human plasma at 20 degrees C demonstrated an 11-17% binding of the labelled lipase to alpha 2M, indicating that this interaction may be of physiological significance.
利用非变性聚丙烯酰胺凝胶电泳和凝胶渗透、锌琼脂糖凝胶柱色谱法以及肝素琼脂糖凝胶柱色谱法，研究了牛脂蛋白脂肪酶（bLPL）与人α2-巨球蛋白（α2M）之间的相互作用。结果表明，体外bLPL与天然α2M非共价结合，但不与用胰凝乳蛋白酶或甲胺处理α2M所产生的受体识别形式结合。当与胰凝乳蛋白酶或甲胺一起孵育时，少量bLPL通过二硫键交换与α2M共价结合。与bLPL形成复合物的α2M仍能与锌琼脂糖凝胶结合，而bLPL失去了与肝素琼脂糖凝胶结合的能力。bLPL与肝素预孵育可阻止其与α2M形成复合物，这表明α2M与bLPL的肝素结合结构域相互作用。在20℃下将125I-bLPL与人血浆孵育的实验表明，标记的脂肪酶与α2M的结合率为11%-17%，这表明这种相互作用可能具有生理意义。
