Comparison of the platelet proteome to proteomes of human HeLa and U2OS cells, encompassing a total of 9696 proteins. (A) All 3 proteomes show a remarkable overlap, which is virtually independent from copy numbers. (B) The distribution of copy numbers is similar for the 3 proteomes. However, because of the smaller cell volume in platelets the mean of the frequency distribution is shifted to lower copy numbers which is in accordance with Lundberg et al who reported a correlation between cell size and protein expression levels.⁵⁵  (C) Contribution of proteins to the total protein mass in the platelet proteome: only 18 proteins account for 20%, 171 proteins for 50%, and 680 proteins for 75% of the total protein mass in human platelets.