大鼠血清磷酸胆碱结合蛋白与血小板的结合。

Binding of rat serum phosphorylcholine binding protein to platelets.

作者信息

Randell E, Mookerjea S, Nagpurkar A

机构信息

Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.

出版信息

Biochim Biophys Acta. 1990 Jun 20;1034(3):281-4. doi: 10.1016/0304-4165(90)90051-w.

DOI:10.1016/0304-4165(90)90051-w

PMID:2364084

Abstract

Rat serum phosphorylcholine binding protein (PCBP), a normal component of rat serum, inhibits in vitro aggregation of rat, rabbit and human platelets by interacting with platelets. In the present study, we have demonstrated the calcium-dependent, specific and saturable binding of 125I-PCBP to rat, rabbit and human platelets. Scatchard analysis of the binding data reveal a class of specific high-affinity binding sites with Kd values of 45.2 +/- 14.9, 26.1 +/- 8.3 and 32.2 +/- 9.9 nM on rat, rabbit and human platelets, respectively. These platelets also expressed a high capacity for binding to 125I-PCBP. The binding of 125I-PCBP to platelets was calcium- and time-dependent, and could be inhibited by phosphorylcholine (IC50 = 5.6 microM). Occupation of these binding sites by PCBP may be responsible for inhibition of platelet aggregation.

摘要

大鼠血清磷酸胆碱结合蛋白（PCBP）是大鼠血清的一种正常成分，它通过与血小板相互作用来抑制大鼠、兔和人的血小板在体外的聚集。在本研究中，我们已证实125I-PCBP与大鼠、兔和人的血小板存在钙依赖性、特异性和饱和性结合。对结合数据进行Scatchard分析表明，在大鼠、兔和人的血小板上分别存在一类特异性高亲和力结合位点，其解离常数（Kd）值分别为45.2±14.9、26.1±8.3和32.2±9.9 nM。这些血小板对125I-PCBP也具有高结合能力。125I-PCBP与血小板的结合是钙依赖性和时间依赖性的，并且可被磷酸胆碱抑制（半数抑制浓度IC50 = 5.6 microM）。PCBP占据这些结合位点可能是抑制血小板聚集的原因。