Huhtala M L, Koistinen R, Palomäki P, Partanen P, Bohn H, Seppälä M
Biochem Biophys Res Commun. 1986 Nov 26;141(1):263-70. doi: 10.1016/s0006-291x(86)80363-1.
We have found that human decidua synthesizes a 34K somatomedin-binding protein PP12. Purification of PP12 by immunochemical techniques from human placenta and adjacent membranes has also yielded lower-molecular weight immunoreactive polypeptides designated as PP12B. An individual 21K fragment of somatomedin-binding protein, and a mixture of fragments with molecular weight from 17K to 20K were isolated from this material using high performance liquid chromatography (HPLC). These fragments reacted with antibodies to native PP12 as shown by Western blotting. They all shared the same N-terminal amino acid sequence: Ala-Pro-Trp-Gln-, which is identical with that obtained for PP12. The 21K fragment was shown to bind somatomedin-C, or IGF-I (insulin-like growth factor-I). Since the N-terminal end of the 21K fragment is identical with that of the 34K somatomedin-binding protein, our results suggest that the 21K fragment is the N-terminal part of somatomedin-binding protein, and the somatomedin-binding domain resides in this N-terminal portion.
我们发现人蜕膜能合成一种34K的生长调节素结合蛋白PP12。通过免疫化学技术从人胎盘及相邻膜中纯化PP12时，还产生了分子量较低的免疫反应性多肽，命名为PP12B。使用高效液相色谱（HPLC）从该材料中分离出一个单独的21K生长调节素结合蛋白片段以及分子量在17K至20K之间的片段混合物。如蛋白质印迹法所示，这些片段与天然PP12的抗体发生反应。它们都具有相同的N端氨基酸序列：Ala-Pro-Trp-Gln-，这与PP12的序列相同。结果表明，21K片段能结合生长调节素-C或胰岛素样生长因子-I（IGF-I）。由于21K片段的N端与34K生长调节素结合蛋白的N端相同，我们的结果提示21K片段是生长调节素结合蛋白的N端部分，且生长调节素结合域位于该N端部分。
