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Table 1 The mean frequencies of the individual amino acids (p(a)) in the genomes of living organisms

From: Optimality of the genetic code with respect to protein stability and amino-acid frequencies

Amino acid p(a) Archaea (%) p(a) Bacteria (%) p(a) Eukaryotes (%) p(a) (%)
Ala 7.85 (2.27) 8.08 (2.61) 6.48 (0.76) 7.80 (2.38)
Arg 5.92 (1.15) 4.99 (1.61) 5.24 (0.49) 5.23 (1.43)
Asp 5.47 (1.57) 5.06 (0.42) 5.31 (0.35) 5.19 (0.81)
Asn 3.40 (1.05) 4.63 (1.97) 4.76 (0.90) 4.37 (1.73)
Cys 0.89 (0.32) 1.00 (0.31) 1.86 (0.35) 1.10 (0.44)
Glu 7.79 (1.13) 6.35 (1.21) 6.64 (0.28) 6.72 (1.24)
Gln 1.90 (0.40) 3.89 (0.95) 4.28 (0.69) 3.45 (1.19)
Gly 7.49 (0.75) 6.70 (1.46) 5.88 (0.72) 6.77 (1.32)
His 1.70 (0.29) 2.07 (0.39) 2.41 (0.21) 2.03 (0.41)
Ile 7.59 (2.19) 7.05 (2.26) 5.48 (0.92) 6.95 (2.16)
Leu 9.65 (1.00) 10.52 (0.66) 9.35 (0.42) 10.15 (0.86)
Lys 6.04 (2.75) 6.43 (2.78) 6.30 (0.69) 6.32 (2.53)
Met 2.49 (0.47) 2.19 (0.37) 2.33 (0.21) 2.28 (0.39)
Phe 4.00 (0.74) 4.57 (0.97) 4.20 (0.59) 4.39 (0.89)
Pro 4.43 (0.92) 3.99 (1.00) 5.15 (0.75) 4.26 (1.01)
Ser 5.93 (1.11) 6.18 (0.77) 8.50 (0.47) 6.46 (1.17)
Thr 4.77 (0.89) 5.15 (0.63) 5.57 (0.32) 5.12 (0.69)
Trp 1.03 (0.20) 1.10 (0.28) 1.13 (0.12) 1.09 (0.25)
Tyr 3.68 (0.66) 3.23 (0.64) 3.03 (0.26) 3.30 (0.63)
Val 7.97 (0.85) 6.87 (1.19) 6.09 (0.42) 7.01 (1.18)
  1. The frequencies p(a) were computed as averages over the frequencies observed in genomes of archaea (Aeropyrum pernix K1, Archaeoglobus fulgidus,Halobacterium sp. NRC-1, Methanococcus jannaschii, Methanobacterium thermoautotrophicum, Pyrococcus abyssi, Pyrococcus horikoshi and Thermoplasma acidophilum), bacteria (Aquifex aeolicus, Bacillus halodurans, Bacillus subtilis, Borrelia burgdorferi, Buchnera aphidicola, Campylobacter jejuni, Chlamydia trachomatis, Deinococcus radiodurans, Escherichia coli K-12, Haemophilus influenzae, Mycobacterium leprae, Mycobacterium tuberculosis, Mycoplasma genitalium, Mycoplasma pneumoniae, Pasteurella multocida, Pseudomonas aeruginosa, Rickettsia prowazekii, Thermotoga maritima, Treponema pallidum, Ureaplasma parvum, Vibrio cholerae and Xylella fastidiosa) and eukaryotes (Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens and Saccharomyces cerevisiae). The last column contains the average frequencies p(a) computed from all these genomes. The standard deviation of the distributions is given in parentheses.