Enzymology of porcine tissue kallikrein.
Enzymology of porcine tissue kallikrein.
复制标题
猪组织激肽释放酶的酶学。
DOI：
--
复制
发表时间：
1983
影响因子：
--
通讯作者：
F. Fiedler
中科院分区：
文献类型：
--
作者：
F. Fiedler
在猪中，下颌下、天然胰腺和尿激肽释放酶是相同的蛋白质，由单个多肽链（α-激肽释放酶）组成。猪组织激肽释放酶与大鼠和小鼠下颌下腺的几种酶、tonin、神经生长因子γ亚基和下颌下腺蛋白酶A显示出非常广泛的序列同源性，几乎与人尿或大鼠下颌下腺激肽释放酶一样高。从胰腺部分自溶物中分离的猪胰腺激肽释放酶携带链内分裂（β-激肽释放酶）。两种链由于其碳水化合物含量的差异而分别以高分子量和低分子量形式存在，并形成四种类型的胰腺β-激肽释放酶（B、A、III和C）。组织激肽释放酶的狭窄特异性的一个原因是它们对P2中庞大的疏水性氨基酸残基的显著的二级特异性。10肽酯Ac-X-ArgOMe与不同的氨基酸在P2的水解猪胰激肽释放酶也表现出不同的个人影响，最有利的残基是苯丙氨酸和亮氨酸，因为它们出现在牛激肽原。相反，所有这些化合物的消化酶胰蛋白酶水解的特异性常数是相似的。在激肽原中甲硫氨酰键周围具有氨基酸序列的肽也被胰激肽释放酶在该键处水解，但特异性常数低三个数量级。在赖氨酸处缺乏切割导致释放胰激肽而不是缓激肽是由于猪胰激肽释放酶不能容纳Arg-Pro离去基团。
In the pig, submandibular, native pancreatic, and urinary kallikreins are the same protein, consisting of a single polypeptide chain (alpha-kallikrein). Porcine tissue kallikrein shows very extensive sequence homology with several enzymes from submandibular glands of rats and mice, tonin, nerve growth factor gamma subunit, and submandibular proteinase A, nearly as high as with human urinary or rat submandibular kallikrein. Porcine pancreatic kallikrein isolated from partial autolyzates of pancreas carries an intrachain split (beta-kallikrein). Both chains exist in a high and low molecular weight form each because of differences in their carbohydrate content and form four types of pancreatic beta-kallikrein (B, A, III, and C). One cause of the narrow specificity of tissue kallikrein is their pronounced secondary specificity for a bulky, hydrophobic amino acid residue in P2. The hydrolysis of 10 peptide esters Ac-X-ArgOMe with different amino acids in P2 by porcine pancreatic kallikrein also showed distinct individual influences, the most favorably residues being phenylalanine and leucine as they occur in bovine kininogen. In contrast, specificity constants for hydrolysis by the digestive enzyme trypsin are similar for all these compounds. A peptide with the amino acid sequence around the methionyl bond cleaved in kininogen is also hydrolyzed by pancreatic kallikrein at this bond, but with a specificity constant three orders of magnitude lower. The lack of cleavage at lysine leading to the release of kallidin instead of bradykinin is due to the inability of porcine pancreatic kallikrein to accommodate an Arg-Pro leaving group.