E. coli 230: yeast 280: human red blood cell 160: rat muscle 260: rat liver 310 mg/ml
||Brown GC. Total cell protein concentration as an evolutionary constraint on the metabolic control distribution in cells. J Theor Biol. 1991 Nov 21 153(2):195-203. p.196 4th paragraphPubMed ID1787736
||K.R. Albe, Butler MH, Wright BE. Cellular concentrations of Enzymes and Their Substrates, J Theor Biol. 1990 Mar 22 143(2):163-95. AND Srivastava DK, Bernhard SA. Enzyme-enzyme interactions and the regulation of metabolic reaction pathways. Curr Top Cell Regul. 1986 28: 1-68.PubMed ID2200929, 3539532
||P.196 4th paragraph: "Proteins occupy a significant proportion of cell volume. Typical protein concentrations in different cell types are: 230mg/ml cell volume in Escherichia coli, 280 mg/ml in yeast, 160 mg/ml in human red blood cells, 260 mg/ml in rat muscle, and 310 mg/ml in rat liver (see primary source Albe et al., 1990 and references therein, see also primary source Srivastava & Bernhard, 1986). Thus, cell protein occupies 20-30% of cell volume in most cells in a range of organisms which are evolutionally widely separated. Clearly large increases in cell protein are unfeasible purely from the point of physical space. In addition the high protein levels mean that the viscosity of the remaining unbound water is increased so that diffusion is potentially limited. Protein levels in cells are close to the solubility limit, i.e. a large increase in soluble protein levels is impossible without "salting out" other soluble proteins (Atkinson, 1969)."