title: Purification of the major mammalian heat shock proteins.
abstract: The major mammalian heat shock or "stress" proteins (molecular masses of 90,000, 72,000, and 73,000 daltons) have been purified from stressed HeLa cells. The 90,000-dalton protein co-purified with small amounts of a 100,000-dalton protein which was identified as one of the other stress proteins in these cells. The 72,000- and 73,000-dalton proteins co-purified throughout the fractionation scheme, apparently as a mixture of monomeric forms of the two proteins. From sedimentation velocity and gel filtration analysis, it was found that the 90,000/100,000-dalton protein mixture had a Stokes radius of 69A and a s20,w value of 5.8 while the 72,000/73,000-dalton protein mixture had a Stokes radius of 42.6A and a s20,w value of 4.3. The purified proteins migrated identically in two-dimensional gel electrophoretograms with their counterparts from total cell lysates of [35S]methionine-labeled stressed HeLa cells. Peptide mapping experiments indicated that the 72,000- and 73,000-dalton proteins contained common peptides while the 90,000- and 100,000-dalton proteins appeared to be distinct. Amino acid analysis of the 90,000- and a mixture of the 72,000/73,000-dalton proteins showed that both contained relatively high amounts of Asp/Asn and Glu/Gln.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells / Q000032:analysis; D006360:Heat-Shock Proteins; D006358:Hot Temperature; D006801:Humans; D008970:Molecular Weight; D011506:Proteins / Q000302:isolation & purification*
chemical_list: D006360:Heat-Shock Proteins; D011506:Proteins