Protease nexin. Properties and a modified purification procedure.
Protease nexin. Properties and a modified purification procedure.
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DOI：
10.1016/s0021-9258(18)88883-4
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发表时间：
1985-06
期刊：
影响因子：
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通讯作者：
Randy W. Scott;Barbara L. Bergman;Ani 1 Bajpai;R. Hersh;Henry Rodriguez;Barry N. Jonesd;Carlos Barredad;S. Watts;Joffre B. Bakera
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文献类型：
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作者：
Randy W. Scott;Barbara L. Bergman;Ani 1 Bajpai;R. Hersh;Henry Rodriguez;Barry N. Jonesd;Carlos Barredad;S. Watts;Joffre B. Bakera
本文介绍了蛋白酶连接蛋白的化学和功能特性，丝氨酸蛋白酶抑制剂释放培养的人成纤维细胞。结果表明，蛋白酶连接蛋白实际上是由成纤维细胞合成的，约占其分泌蛋白的1%。纯化的蛋白酶连接蛋白的氨基酸组成的分析表明，它是进化相关的抗凝血酶III和肝素辅因子II。蛋白酶连接蛋白含有约6%的碳水化合物，2.3%的氨基糖，1.1%的中性糖，和3.0%的唾液酸。根据平衡沉降分析计算的Mr为43，000。蛋白酶连接蛋白是胰蛋白酶样丝氨酸蛋白酶的广谱特异性抑制剂。它与胰蛋白酶反应迅速（kasc = 4.2 +/- 0.4 × 10（6）M-1 s-1），凝血酶（kaslin = 6.0 +/- 1.3 X 10（5）M-1 s-1），尿激酶（kasmin = 1.5 +/- 0.1 × 10（5）M-1 s-1）和纤溶酶（kassoc = 1.3 +/- 0.1 X 10（5）M-1 s-1），并且缓慢抑制因子Xa和神经生长因子的γ亚单位，但不抑制胰凝乳蛋白酶样蛋白酶或白细胞弹性蛋白酶。在肝素存在下，蛋白酶连接蛋白以几乎扩散控制的速率抑制凝血酶。可以检测到蛋白酶连接蛋白的两种肝素亲和力类别。本表征涉及对肝素具有较高亲和力的蛋白酶连接蛋白的级分。低亲和性物质是次要部分，在纯化过程中损失。
The present paper describes chemical and functional properties of protease nexin, a serine protease inhibitor released from cultured human fibroblasts. It is shown that protease nexin is actually synthesized by fibroblasts and represents about 1% of their secreted protein. Analysis of the amino acid composition of purified protease nexin indicates that it is evolutionarily related to antithrombin III and heparin cofactor II. Protease nexin contains approximately 6% carbohydrate, with 2.3% amino sugar, 1.1% neutral sugar, and 3.0% sialic acid. The Mr calculated from equilibrium sedimentation analysis is 43,000. Protease nexin is a broad specificity inhibitor of trypsin-like serine proteases. It reacts rapidly with trypsin (kassoc = 4.2 +/- 0.4 X 10(6) M-1 s-1), thrombin (kassoc = 6.0 +/- 1.3 X 10(5) M-1 s-1), urokinase (kassoc = 1.5 +/- 0.1 X 10(5) M-1 s-1), and plasmin (kassoc = 1.3 +/- 0.1 X 10(5) M-1 s-1), and slowly inhibits Factor Xa and the gamma subunit of nerve growth factor but does not inhibit chymotrypsin-like proteases or leukocyte elastase. In the presence of heparin, protease nexin inhibits thrombin at a nearly diffusion-controlled rate. Two heparin affinity classes of protease nexin can be detected. The present characterization pertains to the fraction of protease nexin having the higher affinity for heparin. The low affinity material, which is the minor fraction, is lost during purification.