40 to 50 %
||Bacteria Escherichia coli
||Ridgway D et al., Coarse-grained molecular simulation of diffusion and reaction kinetics in a crowded virtual cytoplasm. Biophys J. 2008 May 15 94(10):3748-59. doi: 10.1529/biophysj.107.116053 p.3752 left column 2nd paragraphPubMed ID18234819
||Hyun Shik Yun, Juan Hong, Henry C. Lim Analysis of functioning ribosome content in Escherichia coli at different growth rates, Biotechnology Techniques 1991 11/12, Volume 5, Issue 6, pp 471-474 p.471 2nd paragraph (introduction section)
||"Since ribosomes constitute 40–50% of the total cell mass of exponentially
growing E. coli (primary source), a separate ribosomal class was introduced that assumed
a copy number of 18,000 ribosomes per cell (60) contributing to a total
density of 0.34 g/ml (10)."