Demonstration of specific binding sites for pituitary adenylate cyclase activating polypeptide (PACAP) in rat astrocytes.
Demonstration of specific binding sites for pituitary adenylate cyclase activating polypeptide (PACAP) in rat astrocytes.
复制标题
大鼠星形胶质细胞中垂体腺苷酸环化酶激活多肽 (PACAP) 的特异性结合位点的演示。
DOI：
10.1016/0006-291x(90)91132-c
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发表时间：
1990
影响因子：
3.1
通讯作者：
Arimura,A
中科院分区：
文献类型：
--
作者：
Tatsuno,I;Gottschall,PE;Köves,K;Arimura,A
以[125I]PACAP27为标记配体，在大鼠星形胶质细胞中鉴定了PACAP的高、低亲和力结合部位。Scatchard分析表明，高亲和力结合部位的解离常数(Kd)=1.2 2±0.4nM，最大结合容量(Bmax)=82 1±2 18μ/mg蛋白质；低亲和力结合部位的解离常数(Kd)=0.5 9±0.0 6fmmolM，最大结合容量(Bmax)=5 6 3±12 pmmos/mg蛋白质。用PACAP38和与PACAP结构相关的VIP、GHRF、PHI、促胰液素和胰高血糖素等多肽检测[125I]PACAP27结合的特异性。PACAP38完全取代了[125I]PACAP27的结合，Scatchard分析也表明存在两类结合位点，其Kd和Bmax与PACAP27相似。VIP和GHRF与[125I]PACAP27相互竞争，但结合程度远低于未标记的PACAP27。其他被测的多肽不取代[125I]PACAP27在10−6M的结合。
The high and low affinity binding sites for PACAP were identified in rat astrocytes using [125I]PACAP27 as the labeled ligand. Scatchard analysis of displacement of the bound tracer by unlabeled PACAP27 indicated the existence of two classes of binding sites, with the dissociation constant (Kd) = 1.22±0.4 nM, the binding maximal capacity (Bmax) = 821±218 fmols/mg protein for the high affinity binding site, and Kd=0.59±0.06 μM, Bmax=563±12 pmols/mg protein for the low affinity binding site, respectively. The specificity of [125I]PACAP27 binding was tested using PACAP38 and peptides structually related to PACAP, such as VIP, GHRF, PHI, secretin and glucagon. PACAP38 completely displaced the binding of [125I]PACAP27 and Scatchard analysis also indicated the presence of two classes of binding sites with similar Kd and Bmax to those for PACAP27. VIP and GHRF competed with [125I]PACAP27, but to a much lesser extent than unlabeled PACAP27 in binding. Other peptides tested did not displace the binding of [125I]PACAP27 at 10−6M.