CONFORMATIONAL CHARACTERIZATION OF HUMAN ANGIOGENIN BY LIMITED PROTEOLYSIS
CONFORMATIONAL CHARACTERIZATION OF HUMAN ANGIOGENIN BY LIMITED PROTEOLYSIS
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DOI：
10.1007/bf01024885
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发表时间：
1988-08-01
期刊：
影响因子：
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通讯作者：
VALLEE, BL
中科院分区：
文献类型：
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作者：
HARPER, JW;VALLEE, BL
血管生成素的一级结构与牛胰腺核糖核酸酶（RNase）的一级结构有33%相同，但两种蛋白质的酶活性明显不同。类似地，它们对有限蛋白水解的敏感性也不同。与RNA酶相反，血管生成素完全抵抗枯草杆菌蛋白酶的蛋白水解。事实上，在检查的16种蛋白酶中，只有内切蛋白酶Lys-C、胰蛋白酶和胃蛋白酶能够切割血管生成素。即使长时间孵育，内切蛋白酶Lys-C也能选择性切割Lys-60-Asn-61键;产物保留完整的核糖核酸裂解活性。最初，胰蛋白酶也会切割这种相同的键，但随着时间的推移，它会引起广泛的降解。胃蛋白酶在pH 2时裂解Phe-9-Leu-10键，生成血管生成素（10-123），其对核糖体RNA（rRNA）的活性约为天然活性的15%。血管生成素和牛核糖核酸酶对蛋白水解的敏感性和/或切割位点明显不同，尽管它们的结构同源性。这些差异是根据两种蛋白质的氨基酸序列来考虑的。
The primary structure of angiogenin is 33% identical to that of bovine pancreatic ribonuclease (RNase), but the enzymatic activities of the two proteins differ markedly. Similarly, their susceptibilities to limited proteolysis differ as well. In contrast to RNase, angiogenin totally resists proteolysis by subtilisin. Indeed, among 16 proteases examined, only endoprotease Lys-C, trypsin, and pepsin are able to cleave angiogenin. Even with prolonged incubation, endoprotease Lys-C selectively cleaves the Lys-60-Asn-61 bond; the product retains full ribonucleolytic activity. Initially, trypsin also cleaves this same bond, but with time it causes extensive degradation. Pepsin, atpH 2, cleaves the Phe-9-Leu-10 bond, to give angiogenin (10–123), which displays ∼15% of the native activity toward ribosomal RNA (rRNA). The susceptibility to proteolysis and/or the sites of cleavage of angiogenin and bovine RNase differ markedly despite their structural homology. These differences are considered in terms of the amino acid sequences of the two proteins.