Purification and properties of HeLa cell plasma membranes.

A simple method for the preparation of HeLa cell plasma membrane ghosts without the use of cross-linking reagents or Cxatives has been developed. The membranes have been characterized by phase and electron microscopy and by the use of radioactive precursors to RNA, protein, glycoprotein, and lipid. The glycoprotein and polypeptide constituents have been analyzed by sodium dodecyl sulfate-acrylamide gel electrophoresis in conjunction with subfractionation by mild detergents. There appears to be a predominant species of polypeptide and [3H]-L-fucose-labeled glycoprotein having a molecular weight of 40,000 to 45,000. The number of plasma membrane ghosts in a preparation was determined by counting ghosts in a hemacytometer and the yield of ghosts was then found to be in the range of 10 to 20% of the number of cells used for the preparation. Purified plasma membranes labeled for 4 hours or more contained ‘70 to 100% of the total cell trichloroacetic acid insoluble [3H]-L-fucose. Thus, [3H]x.-fucose seems to be a speciCc label for HeLa cell plasma membranes.