Ng C F, Haeggström J Z, Samuelsson B
Department of Cell Biology, University of Medicine and Dentistry of New Jersey, Stratford 08084, USA.
Biochem Biophys Res Commun. 1997 Jul 18;236(2):355-9. doi: 10.1006/bbrc.1997.6953.
The specific binding of leukotriene B4 to its receptor on human leukocyte membranes was enhanced in a dose-dependent manner by metal ions. Mg2+ and Ca2+ were the most potent followed by Mn2+ and Co2+. These divalent cations increased receptor density and did not affect the binding affinity. Addition of the same divalent cations to a partially purified receptor prepared by precipitation with polyethylene glycol produced a greater effect, whereby both binding affinity and receptor density were significantly increased. Zn2+ inhibited activity in both preparations by decreasing the density of receptors. In the membrane preparation, binding activity was decreased by Na+ and increased by K+, while Li+ had no effect. However, in the partially purified receptor preparation, these monovalent cations all increased the binding activity. Our findings show that purification of the leukotriene B4 receptor modifies its response to various monovalent and divalent cations, perhaps by removing certain cellular components involved in receptor regulation.
金属离子以剂量依赖的方式增强了白三烯B4与其在人白细胞膜上受体的特异性结合。Mg2+和Ca2+的作用最强，其次是Mn2+和Co2+。这些二价阳离子增加了受体密度，且不影响结合亲和力。向通过聚乙二醇沉淀制备的部分纯化受体中添加相同的二价阳离子产生了更大的效应，结合亲和力和受体密度均显著增加。Zn2+通过降低受体密度抑制了两种制剂中的活性。在膜制剂中，结合活性被Na+降低，被K+增加，而Li+无影响。然而，在部分纯化的受体制剂中，这些单价阳离子均增加了结合活性。我们的研究结果表明，白三烯B4受体的纯化改变了其对各种单价和二价阳离子的反应，这可能是通过去除某些参与受体调节的细胞成分实现的。
