CHARACTERIZATION OF C3A RECEPTOR-PROTEINS ON GUINEA-PIG PLATELETS AND HUMAN POLYMORPHONUCLEAR LEUKOCYTES
CHARACTERIZATION OF C3A RECEPTOR-PROTEINS ON GUINEA-PIG PLATELETS AND HUMAN POLYMORPHONUCLEAR LEUKOCYTES
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DOI：
10.1002/eji.1830190620
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发表时间：
1989-06-01
影响因子：
5.4
通讯作者：
BITTERSUERMANN, D
中科院分区：
文献类型：
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作者：
GERARDYSCHAHN, R;AMBROSIUS, D;BITTERSUERMANN, D
在豚鼠C3 a敏感性（gp R+）血小板和人多形核白细胞（hu PMNL）上测定C3 a特异性膜受体的表达。用来自gp或hu来源的125 I-标记的C3 a进行的结合研究和应用于结合数据的Scatchard分析揭示了在gp R+血小板上存在两种受体类别：具有约200个结合位点/细胞和Kd = 1.7 ×的高亲和力类别。10-9 M，以及相对低亲和力的类，Kd = 10-8 M，约500个位点/细胞。Hu PMNL表达具有Kd = 3 × 10的同质受体类。10-8 M和40，000个站点/小区。通过（a）将光亲和标记的受体与结合的125 I标记的C3 a交联;（B）使用13个氨基酸残基的C3 a类似物125 I-Nap-Ahx-13光亲和标记受体;和（c）使用化学交联剂（如二琥珀酰亚胺辛二酸酯）将受体与125 I-C3 a交联，实现gp R+血小板上C3 a受体的分子表征。所有这三种技术都产生了非常相似的标记模式。用光亲和标记法，观察到扩散带型，其表观分子量为95-123 kDa，以125 I-C3 a为标记，和85-105 kDa，以125 I-Nap-Ahx-13为标记。125 I-C3 a的化学交联显示出三个不同的条带，分子量约为123、108和95 kDa。减去交联配体的贡献，gp R+血小板上的C3 a受体似乎是一种蛋白质复合物，由1 - 3种组分组成，估计分子量在83-114 kDa之间。
The expression of specific membrane receptors for C3a was determined on guinea pig C3a-sensitive (gp R+) platelets and human polymorphonuclear leukocytes (hu PMNL). Binding studies with 125I-labeled C3a from gp or hu sources and Scatchard analysis applied to the binding data revealed the existence of two receptor classes on gp R+ platelets; a high-affinity class with about 200 binding sites/cell and Kd = 1.7 .times. 10-9 M, and a relatively low-affinity class with Kd = 10-8 M and about 500 sites/cell. Hu PMNL express a homogeneous receptor class with Kd = 3 .times. 10-8 M and 40,000 sites/cell. Molecular characterization of the C3a receptor on gp R+ platelets was achieved by (a) cross-linking photoaffinity-labeled receptors to bound 125I-labeled C3a; (b) photoaffinity labeling receptors with a 13-amino acid residue C3a analogue 125I-Nap-Ahx-13; and (c) use of chemical cross-linkers like disuccinimidylsuberate to cross-link receptors with 125I-C3a. All three techniques gave rise to very similar labeling patterns. With the photoaffinity labeling methods, a diffuse band pattern was observed with an apparent molecular mass of 95-123 kDa with 125I-C3a as label, and 85-105 kDa with 125I-Nap-Ahx-13 as label. Chemical cross-linking of 125I-C3a revealed three distinct bands with molecular masses of approximately 123, 108 and 95 kDa. Subtracting the contribution of the cross-linked ligands, the C3a receptor on gp R+ platelets appears to be a protein complex, consisting of one to three components with estimated molecular masses between 83-114 kDa.