Index to Course Material

Index to Section 2

The Amino Acids

Single and 3-Letter Codes for Amino Acids

All proteins are polymers of the 20 naturally occuring amino acids. They are listed here along with their abbreviations :-

Alanine         Ala     A
Cysteine        Cys     C
Aspartic AciD   Asp     D
Glutamic Acid   Glu     E
Phenylalanine   Phe     F
Glycine         Gly     G
Histidine       His     H
Isoleucine      Ile     I
Lysine          Lys     K
Leucine         Leu     L
Methionine      Met     M
AsparagiNe      Asn     N
Proline         Pro     P       
Glutamine       Gln     Q
ARginine        Arg     R
Serine          Ser     S
Threonine       Thr     T
Valine          Val     V
Tryptophan      Trp     W
TYrosine        Tyr     Y

It is important to take the time to commit the single letter code to memory, as it is invariably used when comparing and aligning sequences of proteins.

Most are easily remembered by their initial letters. Try and invent for yourself memorable mnemonic aids to remember the others. Note that Cysteine and Methionine are the only two sulphur-containing amino acids.

Last updated 9th Oct'96