Table - link proteins/cell
|Milo R. What is the total number of protein molecules per cell volume? A call to rethink some published values. Bioessays. 2013 Dec35(12):1050-5. doi: 10.1002/bies.201300066 p.1052 table 1PubMed ID24114984
|See pointers to refs at right of table
|Abstract: "Here, [investigators] estimate the expected total number of proteins per unit of cell volume using known parameters related to the composition of cells such as the fraction of cell mass that is protein, and the average protein length. Using simple arguments, [they] estimate a range of 2-4 million proteins per cubic micron (i.e. 1 fL) in bacteria, yeast, and mammalian cells."
|P.1053 right column 2nd paragraph: "How do these values compare to previous reports in the literature? Table 1 shows a compilation of values based on published proteome‐wide studies. Notably, in many cases a total sum over all proteins was not reported and was inferred for [investigators'] purposes by summing all measured abundances. While many of the total sums are within twofold of the estimates above, some values – most notably for eukaryotic cells including yeast and mammalian cells – are lower than predicted by as much as a factor of 5–10. This is beyond the uncertainty that can be explained by the ranges of the parameters that went into the estimates. What can possibly explain the marked differences between some reported values and the estimates above? In mass spectrometry measurements, a fraction of the proteome is not reported because the measured values are below the reliable detection limit. Even though the number of such genes can be significant (measuring in thousands), current sensitivity is so good that the contribution to the overall sum is expected to be negligible, amounting to much less than 20% of the overall count. The small quantitative effect of the proteins that are below the detection limit is in line with the fact that the top 1,000 most highly expressed proteins in a cell make up over 80% of the proteome mass as calculated by the author from the data published in papers referred to in Table 1." Please see note beneath table