Scanu A M, Pfaffinger D, Lee J C, Hinman J
Department of Medicine, University of Chicago, IL.
Biochim Biophys Acta. 1994 Oct 21;1227(1-2):41-5. doi: 10.1016/0925-4439(94)90104-x.
Human lipoprotein(a) or Lp(a) binds, like plasminogen, to lysine Sepharose. However, contrary to plasminogen in which kringles 1 and 4 have been implicated, the binding site or sites on apo(a), the specific glycoprotein of Lp(a), have not been determined. For the first time we now report the occurrence of a human Lp(a) that has a mutant form of apo(a) where Arg has replaced Trp in position 72 of kringle 4-37 and is unable to bind to lysine Sepharose. This observation suggests that Trp72 of apo(a) kringle 4-37 may play a dominant role in lysine binding. Lysine binding has been associated with the thrombogenic potential of Lp(a). Thus, the Trp72-->Arg mutation may render Lp(a) 'benign' from the cardiovascular viewpoint.
人脂蛋白(a)即Lp(a)，与纤溶酶原一样，能结合到赖氨酸琼脂糖上。然而，与已证实kringle 1和4参与其中的纤溶酶原不同，Lp(a)的特异性糖蛋白载脂蛋白(a)上的一个或多个结合位点尚未确定。现在我们首次报道了一种人Lp(a)的存在，其载脂蛋白(a)具有突变形式，其中kringle 4 - 37的第72位的色氨酸被精氨酸取代，且无法结合到赖氨酸琼脂糖上。这一观察结果表明，载脂蛋白(a) kringle 4 - 37的色氨酸72可能在赖氨酸结合中起主导作用。赖氨酸结合与Lp(a)的血栓形成潜能有关。因此，从心血管角度来看，色氨酸72突变为精氨酸可能使Lp(a)变得“无害”。
