Misumi Y, Sohda M, Ohkubo K, Takami N, Oda K, Ikehara Y
Department of Biochemistry and Radioisotope Laboratory, Fukuoka University School of Medicine.
J Biochem. 1990 Aug;108(2):230-4. doi: 10.1093/oxfordjournals.jbchem.a123185.
A cDNA clone for alpha 1-protease inhibitor (pc alpha 1P1212) was isolated from a lambda ZAP rat liver cDNA library. The 1.4 kb cDNA insert of pc alpha 1P1212 contained an open reading frame that encodes a 411-residue polypeptide (46,125 Da), in which a signal peptide of 24 residues was identified by comparison with the NH2-terminal sequence of the purified protein. Three potential sites for N-linked glycosylation were found in the molecule, accounting for the difference in molecular mass between the predicted form and the purified protein (56 kDa). The deduced primary structure of rat alpha 1-protease inhibitor showed 68.5% homology to that of the human inhibitor. We then constructed the expression plasmid pSV2 alpha 1PI from pSV2-gpt and pc alpha 1P1212, and transfected it into COS-1 cells. The transfected cells synthesized a molecule which was precipitated with anti-(rat alpha 1-protease inhibitor)-IgG and had the same molecular size as that of the inhibitor produced by rat hepatocytes.
从λZAP大鼠肝脏cDNA文库中分离出α1-蛋白酶抑制剂的cDNA克隆（pcα1P1212）。pcα1P1212的1.4kb cDNA插入片段包含一个开放阅读框，编码一个411个残基的多肽（46,125Da），通过与纯化蛋白的NH2-末端序列比较，确定其中一个24个残基的信号肽。在该分子中发现了三个潜在的N-连接糖基化位点，这解释了预测形式与纯化蛋白（56kDa）之间分子量的差异。推导的大鼠α1-蛋白酶抑制剂一级结构与人抑制剂的一级结构具有68.5%的同源性。然后我们从pSV2-gpt和pcα1P1212构建了表达质粒pSV2α1PI，并将其转染到COS-1细胞中。转染细胞合成了一种分子，该分子可被抗（大鼠α1-蛋白酶抑制剂）-IgG沉淀，并且与大鼠肝细胞产生的抑制剂具有相同的分子大小。
