Amino Acid Abbreviations

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Amino Acid Abbreviations

This article provides you with the table of amino acid abbreviations that are used with the International Nucleotide Sequence Database. Have a look…

French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet were the first to discover amino acids, in 1806. They isolated a compound in asparagus and found it to be asparagine, making asparagine as the first amino acid to be discovered. Then, in 1810, the second amino acid to be discovered was cystine. By 1884, the monomer of cystine―cysteine was discovered. Around 1820, two more amino acids were discovered, namely, glycine and leucine.

Amino Acids and Their Functions

Amino acids are those molecules that contain an amine group, a carboxylic acid group, and a side chain. This side varies in different amino acids. Amino acids contain carbon, hydrogen, oxygen, and nitrogen elements. These are very important molecules in biochemistry, and called alpha-amino acids. They have a general formula―h2NCHRCOOH, where the R is an organic substituent.

Amino acids are important as they have many metabolic functions. They are the building blocks of proteins that have a linear chain of amino acids. The primary structure of a protein is an amino acid that has turned into a three-dimensional structure. These acids are linked together to form long chains, and each varying sequence leads to the formation of different proteins.

The acids form parts of co-enzymes, or act as precursors for the biosynthesis of molecules. Thus, amino acids are a very important part of nutrition, as they play a central role in biochemistry. They are also used in the food industry, and for production of biodegradable plastics, drugs, and even as chiral catalysts.


As mentioned above, each amino acid has one amine and one acid functional group. They get their specific properties from the different R groups attached. Amino acids have special common names, and most of the time, 3 letter amino acid abbreviations are used. The single letter abbreviations are used in case of long protein structures.

Name of Amino Acid 3 Letter Abbreviation Single Letter Abbreviation
Alanine Ala A
Arginine Arg R
Asparagine Asn N
Aspartic acid Asp D
Cysteine Cys C
Glutamine Gln Q
Glutamic cid Glu E
Glycine Gly G
Histidine His H
Isoleucine Ile I
Leucine Leu L
Lysine Lys K
Methionine Met M
Phenylalanine Phe F
Proline Pro P
Serine Ser S
Threonine Thr T
Tryptophan Trp W
Tyrosine Tyr Y
Valine Val V

Ambiguous Amino Acids

Ambiguous Amino Acids 3-Letter 1-Letter
Asparagine or aspartic acid Asx B
Glutamine or glutamic acid Glx Z
Leucine or Isoleucine Xle J
Unspecified or unknown amino acid Xaa/ Unk X

These abbreviations are according to the International Nucleotide Sequence Database.

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