Durliat M, Komano O, Correc P, Bertrand O, Cochet S, Caignard A, Martin F, Burtin P
Laboratorie d'Immunochimie, UPR 277 Centre National de la Recherche Scientifique, IRSC, Villejuif, France.
Br J Cancer. 1992 Jul;66(1):51-6. doi: 10.1038/bjc.1992.215.
Cells from rat carcinoma cell lines PROb (giving progressive tumours) and REGb (giving regressive tumours) have cell surface receptors which bind specifically rat plasminogen and plasmin. Affinity for Pg was found to be higher in PROb (Kd = 10(-7) M) than in REGb cells (Kd = 5.10(-7) M) but with a concomitant decrease in the number of binding sites, 0.9 x 10(6)/cell (range from 0.6 to 1.2 x 10(6)) in PROb vs 3.6 x 10(6)/cell (range 1.2 to 6 x 10(6)) in REGb cells. The number and the affinity of binding sites varied in an opposite way in PROb and REGb cells. The difference in affinity parameters was unrelated to the degree of invasiveness of tumour cells in syngenetic rats. Bound plasmin retained its enzymatic activity, which indicates that its binding does not involve the catalytic active site. In cell solubilisates plasminogen receptor appeared as one major band situated in the area of 50-60 kDa.
来自大鼠癌细胞系PROb（产生进行性肿瘤）和REGb（产生退行性肿瘤）的细胞具有可特异性结合大鼠纤溶酶原和纤溶酶的细胞表面受体。发现PROb细胞（Kd = 10^(-7) M）对纤溶酶原的亲和力高于REGb细胞（Kd = 5×10^(-7) M），但结合位点数量随之减少，PROb细胞为0.9×10^6/细胞（范围为0.6至1.2×10^6），而REGb细胞为3.6×10^6/细胞（范围为1.2至6×10^6）。PROb和REGb细胞中结合位点的数量和亲和力呈相反变化。亲和力参数的差异与同基因大鼠中肿瘤细胞的侵袭程度无关。结合的纤溶酶保留了其酶活性，这表明其结合不涉及催化活性位点。在细胞溶解产物中，纤溶酶原受体表现为位于50 - 60 kDa区域的一条主要条带。
