IUPAC code tables | Print |
These IUPAC tables list codes used to represent ambiguous DNA bases and amino acid residues.

Amino acid codes

Nucleic acid codes
1-letter 3-letter description
A Ala Alanine
R Arg Arginine
N Asn Asparagine
D Asp Aspartic acid
C Cys Cysteine
Q Gln Glutamine
E Glu Glutamic acid
G Gly Glycine
H His Histidine
I Ile Isoleucine
L Leu Leucine
K Lys Lysine
M Met Methionine
F Phe Phenylalanine
P Pro Proline
S Ser Serine
T Thr Threonine
W Trp Tryptophan
Y Tyr Tyrosine
V Val Valine
B Asx Aspartic acid or Asparagine
Z Glx Glutamine or Glutamic acid
X Xaa Any amino acid
code description
A Adenine
C Cytosine
G Guanine
T Thymine
U Uracil
R Purine (A or G)
Y Pyrimidine (C, T, or U)
M C or A
K T, U, or G
W T, U, or A
S C or G
B C, T, U, or G (not A)
D A, T, U, or G (not C)
H A, T, U, or C (not G)
V A, C, or G (not T, not U)
N Any base (A, C, G, T, or U)