A NEW HIGH MOLECULAR WEIGHT EXTRACELLULAR MATRIX PROTEIN

在研究细胞外基质合成的过程中， 儿童肿瘤，我们遇到了一个以前未确定的，高 分泌到条件培养基中的分子量（500，000 D）蛋白 几种肿瘤细胞系。 这种蛋白质的分泌与 层粘连蛋白、IV型胶原和纤连蛋白，但在免疫学上不同 从此。 它也不与基底膜抗体反应 蛋白聚糖。 它不能用放射性标记的硫酸钠标记， 糖基前体，这进一步将其与常规的 蛋白聚糖 选择性酶降解研究表明， 蛋白质对胰蛋白酶和胃蛋白酶敏感，而对胶原酶和GAG降解敏感 酶不敏感。 旋转阴影的超微结构研究，纯化 分子显示出长度超过700 nm的单一、无支链的链。 的 分子与层粘连蛋白和IV型胶原蛋白在正常条件下共纯化 情节 目前的努力旨在设计准备性的 纯化技术，这将允许纯化的数量 足以启动单克隆抗体和生物制品的产生， 功能研究

In the course of studying extracellular matrix synthesis by various childhood tumors, we have encountered a previously unidentified, high molecular weight (500,000 D) protein secreted into the conditioned medium of several tumor cell lines. This protein is secreted in connection with laminin, type IV collagen, and fibronectin, but is immunologically distinct therefrom. It is also nonreactive with antibodies to basal lamina proteoglycan. It fails to label with radiolabelled sodium sulfate or glycosyl precursors, which further distinguishes it from conventional proteoglycans. Selective enzymatic degradation studies indicate that the protein is trypsin and pepsin sensitive, but collagenase and GAG degrading enzyme insensitive. Ultrastructural studies of rotary shadowed, purified molecules reveal a single, unbranched chain of over 700 nm length. The molecule co-purifies with laminin and type IV collagen under normal circumstances. Current efforts are aimed at devising preparative purification techniques which will allow purification of quantities sufficient to initiate the generation of monoclonal antibodies and biologic function studies.