title: The high molecular weight proteins released from cultured cells.
abstract: Studies have been performed with the serum-free culture medium taken from several fibroblast monolayer culture lines. A high molecular weight protein fraction was separated from the concentrated medium by sucrose density gradient centrifugation. Polyacrylamide gel electrophoresis was used to assess the degree of purification obtained. In the electron microscope the negatively stained high molecular weight proteins were found to closely resemble the alpha2-macroglobulins. The suggestion that these proteins from cultured cells resemble the cylindrical protein complex isolated from mammalian erythrocyte ghosts is not supported by this study. The results are discussed in the light of the extensive literature now available on the electron microscopy of high molecular weight proteins.
mesh_terms: D001798:Blood Proteins; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000032:analysis; D005347:Fibroblasts / Q000032:analysis*; D006367:HeLa Cells / Q000032:analysis; D006801:Humans; D005779:Immunodiffusion; D008854:Microscopy, Electron; D008970:Molecular Weight; D011506:Proteins / Q000302:isolation & purification; D000511:alpha-Macroglobulins
chemical_list: D001798:Blood Proteins; D011506:Proteins; D000511:alpha-Macroglobulins