Limited cleavage of cellular fibronectin by plasminogen activator purified from transformed cells.
Limited cleavage of cellular fibronectin by plasminogen activator purified from transformed cells.
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从转化细胞中纯化的纤溶酶原激活剂对细胞纤连蛋白进行有限裂解。
DOI：
10.1073/pnas.84.9.2776
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发表时间：
1987
影响因子：
11.1
通讯作者：
Sullivan,LM
中科院分区：
文献类型：
--
作者：
Quigley,JP;Gold,LI;Schwimmer,R;Sullivan,LM
在其天然底物纤溶酶原缺失或被抑制的条件下，考察了纤溶酶原激活剂(PA)的底物特异性和直接催化活性。从转化的鸡成纤维细胞培养物中纯化的PA与潜在底物的纯化制剂孵育。从正常鸡成纤维细胞细胞外基质中分离出的粘附性糖蛋白纤维连接蛋白，在没有纤溶酶原的情况下，被PA有限但特异地切割。聚丙烯酰胺凝胶在还原和非还原条件下的裂解产物分析表明，PA介导的裂解发生在纤维连接蛋白的羧基末端附近，但在链间二硫键的氨基末端，从而破坏了天然的二聚体纤维连接蛋白分子。在相同的条件下，鸡卵清蛋白没有被切割，而已建立的底物鸡纤溶酶原被广泛转化为纤溶酶。一种针对禽类PA的单抗，被证明能抑制无纤溶酶原、细胞介导的基质降解，特异性地抑制纤维连接蛋白的切割。人的PA，尿激酶，也在无纤溶酶原的条件下裂解纤维连接蛋白，产生有限数量的高分子量裂解产物。
The substrate specificity and direct catalytic activity of plasminogen activator (PA) was examined under conditions where its natural substrate, plasminogen, was missing or inhibited. PA, purified from cultures of transformed chicken fibroblasts, was incubated with purified preparations of potential substrates. The adhesive glycoprotein fibronectin, isolated from normal chicken fibroblast extracellular matrix, underwent limited but specific cleavage by PA in the absence of plasminogen. Analysis of the cleavage products by polyacrylamide gels under both reducing and nonreducing conditions indicated that PA-mediated cleavage occurred near the carboxyl terminus of fibronectin but on the amino-terminal side of the interchain disulfide bridge, thus disrupting the native dimeric fibronectin molecule. Under the identical conditions, chicken ovalbumin was not cleaved while the established substrate, chicken plasminogen, was extensively converted to plasmin. A monoclonal antibody, directed against avian PA and shown to inhibit plasminogen-free, cell-mediated matrix degradation, specifically inhibited the fibronectin cleavage. A human PA, urokinase, also cleaved fibronectin under plasminogen-free conditions yielding a limited number of high molecular weight cleavage products.