Fraction of bulk protein that is proteasomes in HeLa cells

Range ~0.6 %
Organism Human Homo sapiens
Reference Hendil KB, Hartmann-Petersen R, Tanaka K. 26 S proteasomes function as stable entities. J Mol Biol. 2002 Jan 25 315(4):627-36. p.631 right column 3rd paragraphPubMed ID11812135
Primary Source Hendil KB. The 19 S multicatalytic "prosome" proteinase is a constitutive enzyme in HeLa cells. Biochem Int. 1988 Sep17(3):471-7.PubMed ID2849441
Method Immunochemical analysis ("The amount of radioactivity recovered by immunoprecipitation was about 0.6% of the initial radioactivity in the cells, in agreement with the prosome contents of the cells as determined by immunoassay" -primary source, p.476 2nd paragraph)
Comments "Provided that the initiation of degradation of a peptide chain involves an obligatory disassembly and reassembly of 26 S proteasomes, what would the expected rate of exchange be? A rough estimate can be made in the following way: 20 S proteasomes make up about 0.6 % of bulk protein in HeLa cells [primary source]. About 50 % of the bulk protein is soluble (results not shown) so each gram of soluble cell protein in extracts contained about 1.2 % or 12 mg of 20 S proteasomes with a molecular mass of about 720 kDa, [ref 4] corresponding to 1.7×10^-8 moles."
Entered by Uri M
ID 108028