Plasminogen activator: The major secreted neutral protease of cultured skeletal muscle cells
Plasminogen activator: The major secreted neutral protease of cultured skeletal muscle cells
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纤溶酶原激活剂：培养的骨骼肌细胞的主要分泌中性蛋白酶
DOI：
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发表时间：
1982
影响因子：
5.6
通讯作者：
K. Romstedt
中科院分区：
文献类型：
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作者：
B. Festoff;Michael R. Patterson;K. Romstedt
克隆小鼠骨骼肌细胞在培养和与神经细胞的突触中分化，发现分泌高水平的蛋白酶活性，通过125I -纤维蛋白测定。分泌的蛋白水解活性90%以上依赖于培养基中纤溶酶原的存在，pH值在7 ~ 8时达到最佳。该活性不受正乙基马来酰亚胺、胃抑素、EDTA或EGTA的抑制。在毫摩尔浓度下，大豆typsin抑制剂、epsilon氨基己酸、Trasylol或lepeptin均可获得90%以上的抑制作用。1mm氟磷酸二异丙基几乎完全抑制，表明在催化位点存在丝氨酸残留物。与高水平的分泌活性相反，在细胞裂解物中检测到较低的稳态水平的细胞相关蛋白酶活性。高水平的纤溶酶原激活剂分泌到培养肌肉细胞的培养基中，表明这种细胞外蛋白酶活性在肌肉损伤后发育和重塑期间的肌肉发生中起作用。这些信息可能有助于理解实验性和病理性失神经支配中神经肌肉接触的初始变性。
Clonal mouse skeletal muscle cells which differentiate in culture and from synpases with neuronal cells were found to secrete high levels of protease activity as measured with an 125I‐fibrin assay. The secreted proteolytic activity was more than 90% dependent upon the presence of plasminogen in the medium, and had a pH optimum at 7 to 8. This activity was not inhibited by n‐ethylmaleimide, pepstatin, EDTA, or EGTA. At millimolar concentrations, greater than 90% inhibition was obtained with either soybean typsin inhibitor, epsilon aminocaproic acid, Trasylol, or leupeptin. Almost complete inhibition occured with 1 mM diisopropylfluorophosphate suggesting the presence of a serine residue at the catalytic site. In contrast to the high levels of secreted activity, a lower steady‐state level of cell‐associated protease activity was detected in cell lysates. The high level of plasminogen activator secreted into the medium of cultured muscle cells suggests a role for such extracellular protease activity in myogenesis during development and remodeling following muscle injury. Such information may be useful in understanding the initial degeneration of neuromusclar contacts in experimental and pathologic denervation.