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Peptide Molecular Weight Calculator

Molecular Weight notes

The molecular weights below are those of the free acid and not the residue, which is used in the calculations performed by the Peptide Properties Calculator. Subtracting the weight of a mole of water (18g/mol) yields the molecular weight of the residue. The weights used for Glx and Asx are averages.

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Amino Acid Codes TableM.W.

  • 89.09A - Alanine (Ala)
  • 121.16C - Cysteine (Cys)
  • 133.10D - Aspartic Acid (Asp)
  • 147.13E - Glutamic Acid (Glu)
  • 165.19F - Phenylalanine (Phe)
  • 75.07G - Glycine (Gly)
  • 155.16H - Histidine (His)
  • 131.18I - Isoleucine (Ile)
  • 146.19K - Lysine (Lys)
  • 131.18L - Leucine (Leu)
  • 149.21M - Methionine (Met)
  • 132.12N - Asparagine (Asn)
  • 115.13P - Proline (Pro)
  • 146.15Q - Glutamine (Gln)
  • 174.20R - Arginine (Arg)
  • 105.09S - Serine (Ser)
  • 119.12T - Threonine (Thr)
  • 117.15V - Valine (Val)
  • 204.23W - Tryptophan (Trp)
  • 181.19Y - Tyrosine (Tyr)