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Purification of the major mammalian heat shock proteins.

Authors
Type
Published Article
Journal
The Journal of biological chemistry
Publication Date
Volume
257
Issue
24
Pages
14949–14959
Identifiers
PMID: 7174676
Source
Medline
License
Unknown

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.

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