PURIFICATION OF THE PLASMIN RECEPTOR FROM HUMAN CARCINOMA-CELLS AND COMPARISON TO ALPHA-ENOLASE

We have characterized a receptor for plasmin (Pli-R) from a human tumo r cell line, MCF7MF. The Pli-R was purified from a MCF7 0.1% Triton X- 100 solubilisate by affinity chromatography. A protein of 55-60 kDa wa s obtained, which bound plasminogen and plasmin specifically. Chemical cross-linking of Mr 90 kDa [(125)]-Pli to the surface of MCF7 cells w ith DSP results in the formation of a labelled complex of Mr 145 kDa, suggesting a Mr of 55-60 kDa for the receptor. Comparing Pli-R with al pha-enolase (a candidate for plasminogen receptor in U937 cells) we ha ve found a high homology between both proteins, but not an identity.