Titani K, Fujikawa K, Enfield D L, Ericsson L H, Walsh K A, Neurath H
Proc Natl Acad Sci U S A. 1975 Aug;72(8):3082-6. doi: 10.1073/pnas.72.8.3082.
The amino-acid sequence of the heavy chain of bovine blood coagulation factor X1 (Stuart factor) isolated before and after activation has been determined. Sequence analysis was performed on fragments obtained by cleavage with cyanogen bromide and by tryptic digestion. Comparison of the complete sequence with those of other hepatic and pancreatic serine proteases demonstrates homology of the heavy chain of activated factor X1 (factor X1a) with the B chain of bovine thrombin as well as with bovine trypsin, chymotrypsins A and B, and porcine elastase. The activation peptide cleaved near the amino terminus by a protease from Russell's viper venom differs in both size and sequence from those of other serine proteases. With three exceptions, all of the residues which are important in the catalytic functions of trypsin and chymotrypsin occur in corresponding loci in the heavy chain of factor Xa. These finding suggest that the three-dimensional structure of the heavy chain is similar to that of the pancreatic serine proteases and that these enzymes have evolved from a common ancestral gene.
已确定牛凝血因子X1（斯图尔特因子）重链在激活前后的氨基酸序列。对通过溴化氰裂解和胰蛋白酶消化获得的片段进行了序列分析。将完整序列与其他肝脏和胰腺丝氨酸蛋白酶的序列进行比较，结果表明活化因子X1（因子X1a）的重链与牛凝血酶的B链以及牛胰蛋白酶、胰凝乳蛋白酶A和B以及猪弹性蛋白酶具有同源性。由罗素蝰蛇毒中的一种蛋白酶在氨基末端附近切割的激活肽，其大小和序列与其他丝氨酸蛋白酶的不同。除了三个例外，在胰蛋白酶和胰凝乳蛋白酶催化功能中起重要作用的所有残基都出现在因子Xa重链的相应位点。这些发现表明，重链的三维结构与胰腺丝氨酸蛋白酶的相似，并且这些酶是由一个共同的祖先基因进化而来的。
