Amino acid difference formula to help explain protein evolution

Science. 1974 Sep 6;185(4154):862-4. doi: 10.1126/science.185.4154.862.


A formula for diference between amino acids combines properties that correlate best with protein residue substitution frequencies: composition, polarity, and molecular volume. Substitution frequencies agree much better with overall chemical difference between exchanging residues than with minimum base changes between their codons. Correlation coefficients show that fixation of mutations between dissimilar amino acids is generally rare.

MeSH terms

  • Amino Acids*
  • Biological Evolution
  • Genetic Code*
  • Mathematics
  • Models, Biological*
  • Mutation*
  • Protein Biosynthesis*
  • Protein Conformation
  • RNA, Messenger


  • Amino Acids
  • RNA, Messenger