Vogel R, Assfalg-Machleidt I, Esterl A, Machleidt W, Müller-Esterl W
Department of Clinical Chemistry and Clinical Biochemistry, University of Munich, Federal Republic of Germany.
J Biol Chem. 1988 Sep 5;263(25):12661-8.
Low molecular weight kininogen from human plasma was subjected to limited proteolysis with trypsin, chymotrypsin, elastase, and bromelain, and the resulting fragments of 20,000 or 40,000 Da were isolated. Amino-terminal sequence analysis of the fragments disclosed for the various proteinases eight independent cleavage sites distinct from the typical kallikrein cleavage sites flanking the kinin region. All the identified cleavage sites cluster in two stretches of 11-12 residues of the kininogen heavy chain. These short segments represent the primary attack sites for proteinases ("proteinase-sensitive regions") in the heavy chain portion of human low molecular weight kininogen. The amino acid sequences of the two proteinase-sensitive regions are mutually homologous; they are further characterized by the presence of a single copy each of the consensus tetrapeptide Cys-X-Gly-Cys known to form a narrow disulfide loop (Kellermann, J., Thelen, C., Lottspeich, F., Henschen, A., Vogel, R., and Müller-Esterl, W. (1987) Biochem. J. 247, 15-21). The proteinase-sensitive regions are located at the junctions of the three cystatin-like domains constituting the kininogen heavy chain. Proteolytic cleavage at the sensitive regions dissects the kininogen heavy chain and releases single domains of 20,000 Da and combined domains of 40,000 Da which can function as cysteine proteinase inhibitors. The presence of kininogen heavy chain domains in plasma samples under pathologic conditions suggests that cleavage of the proteinase-sensitive regions might also occur in vivo.
将人血浆中的低分子量激肽原用胰蛋白酶、胰凝乳蛋白酶、弹性蛋白酶和菠萝蛋白酶进行有限的蛋白水解，然后分离出产生的20,000或40,000道尔顿的片段。对这些片段进行氨基末端序列分析，发现各种蛋白酶有八个独立的切割位点，这些位点不同于激肽区域两侧典型的激肽释放酶切割位点。所有已鉴定的切割位点都聚集在激肽原重链的两段11 - 12个残基的区域内。这些短片段代表了人低分子量激肽原重链部分中蛋白酶的主要攻击位点（“蛋白酶敏感区域”）。这两个蛋白酶敏感区域的氨基酸序列相互同源；它们的进一步特征是各自存在一个已知能形成狭窄二硫键环的共有四肽Cys-X-Gly-Cys的单拷贝（凯勒曼，J.，特伦，C.，洛茨皮希，F.，亨申，A.，沃格尔，R.，和米勒-埃斯特尔，W.（1987年）《生物化学杂志》247卷，15 - 21页）。蛋白酶敏感区域位于构成激肽原重链的三个胱抑素样结构域的交界处。在敏感区域进行蛋白水解会切割激肽原重链，并释放出20,000道尔顿的单个结构域和40,000道尔顿的组合结构域，这些结构域可作为半胱氨酸蛋白酶抑制剂发挥作用。病理条件下血浆样本中激肽原重链结构域的存在表明，蛋白酶敏感区域的切割在体内也可能发生。
