Li X A, Yutani C, Shimokado K
Department of Biochemistry, Taishan Medical College, Taian, Shandong, P. R. China.
Biochem Biophys Res Commun. 1998 Mar 6;244(1):249-52. doi: 10.1006/bbrc.1998.8248.
Serum amyloid P component (SAP) is a glycoprotein in human plasma. We previously showed that SAP is specifically localized in human atherosclerotic lesions, suggesting that SAP may play a role in atherogenesis. In this study, the interactions between human SAP and high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were investigated by using a solid phase plate assay. Biotinylated SAP bound to immobilized HDL and VLDL in a calcium-dependent, saturable manner. The SAP-HDL and SAP-VLDL bindings reached saturation at 4 nM and 16 nM of SAP, respectively. The bindings were inhibited by native SAP in a dose-dependent manner. No binding between SAP and LDL was found in the presence of calcium or EDTA, which indicates the specificity of SAP-lipoproteins interactions. These results suggest that the function of SAP is related to its capability to interact with lipoproteins and this may have important implications in atherosclerosis and in amyloidosis.
血清淀粉样蛋白P成分（SAP）是人体血浆中的一种糖蛋白。我们之前表明，SAP特异性定位于人类动脉粥样硬化病变中，这表明SAP可能在动脉粥样硬化形成中发挥作用。在本研究中，通过使用固相板分析法研究了人SAP与高密度脂蛋白（HDL）、低密度脂蛋白（LDL）和极低密度脂蛋白（VLDL）之间的相互作用。生物素化的SAP以钙依赖性、可饱和的方式与固定化的HDL和VLDL结合。SAP-HDL和SAP-VLDL结合分别在4 nM和16 nM的SAP时达到饱和。天然SAP以剂量依赖性方式抑制这些结合。在存在钙或乙二胺四乙酸（EDTA）的情况下，未发现SAP与LDL之间有结合，这表明SAP与脂蛋白相互作用具有特异性。这些结果表明，SAP的功能与其与脂蛋白相互作用的能力有关，这可能在动脉粥样硬化和淀粉样变性中具有重要意义。
