Inhibition of biological activity of multiplication-stimulating activity by binding to its carrier protein.
Inhibition of biological activity of multiplication-stimulating activity by binding to its carrier protein.
复制标题
通过与其载体蛋白结合来抑制增殖刺激活性的生物活性。
DOI：
--
复制
发表时间：
1980
影响因子：
11.1
通讯作者：
G. Smith
中科院分区：
文献类型：
--
作者：
D. Knauer;G. Smith
水牛大鼠肝细胞（BRL-3A）在培养过程中产生的增殖刺激活性（MSA）与生长调节多肽somatomedin家族有关。MSA浓度为10-200 ng/ml时，可刺激正常鸡胚成纤维细胞（CEF）葡萄糖转运和DNA合成。在brl - 3a条件培养基中发现的MSA与血清中的生长激素一样，不是作为游离激素存在，而是与特定的高分子量载体蛋白结合。在本报告中，我们证明纯化的MSA载体蛋白（MCP）通过刺激葡萄糖运输和DNA合成来抑制MSA在CEF上的生物活性。此外，纯化的MCP竞争性地抑制125i标记的MSA与这些细胞的结合。在胰岛素作为有丝分裂剂的对照实验中，MCP对这些生物学反应没有影响。这些结果表明，MCP的抑制作用是与MSA特异性相互作用的结果，并支持了细胞可能对与其血清载体蛋白结合的生长抑素无反应的假设。
Multiplication-stimulating activity (MSA) produced by Buffalo rat liver cells (BRL-3A) in culture is related to the somatomedin family of growth regulatory polypeptides. MSA will stimulate glucose transport and DNA synthesis in normal chicken embryo fibroblasts (CEF) at concentrations of 10-200 ng/ml. MSA found in BRL-3A-conditioned medium, like the somatomedins in serum, does not exist as the free hormone but is bound to a specific high molecular weight carrier protein. In this report we demonstrate that purified MSA carrier protein (MCP) inhibits the biological activity of MSA on CEF as measured by the stimulation of glucose transport and DNA synthesis. In addition, purified MCP competitively inhibits the binding of 125I-labeled MSA to these cells. In control experiments in which insulin was used as the mitogenic agent, MCP had no effect on these biological responses. These results indicate that the inhibitory effect of MCP is the result of specific interaction with MSA and support the hypothesis that cells may be unresponsive to somatomedins bound to their serum carrier proteins.