Amino Acid Codes Abbreviation1 letter abbreviationAmino acid name Ala A Alanine Arg R Arginine Asn N Asparagine Asp D Aspartic acid Cys C Cysteine Gln Q Glutamine Glu E Glutamic acid Gly G Glycine His H Histidine Ile I Isoleucine Leu L Leucine Lys K Lysine Met M Methionine Phe F Phenylalanine Pro P Proline Pyl O Pyrrolysine Ser S Serine Sec U Selenocysteine Thr T Threonine Trp W Tryptophan Tyr Y Tyrosine Val V Valine Asx B Aspartic acid or Asparagine Glx Z Gultamic acid or Glutamine Xaa X Any amino acid Xle J Leucine or Isoleucine TERM Termination Codon Request a quote for custom peptide synthesis GMP (Clinical Grade) NON-GMP (Research Grade)