List of amino acids and their abbreviations

This table is included for future reference.

Amino acid 3-letter abbreviation 1-letter abbreviation
Alanine Ala A
Arginine Arg R
Asparagine Asn N
Aspartic acid Asp D
Cysteine Cys C
Glutamic acid Glu E
Glutamine Gln Q
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

20
Amino acids, their single-letter data-base codes (SLC), and their corresponding DNA codons

 

Amino Acid

SLC

DNA codons

Isoleucine

I

ATT,
ATC, ATA

Leucine  

L

CTT, CTC, CTA, CTG, TTA, TTG
Valine

V

GTT, GTC, GTA, GTG
Phenylalanine  

F

TTT, TTC
Methionine M ATG
Cysteine  C

TGT, TGC

Alanine      

A

GCT, GCC,
GCA, GCG

Glycine  

G

GGT, GGC, GGA, GGG
Proline      

P

CCT, CCC, CCA, CCG
Threonine  

T

ACT, ACC, ACA, ACG
Serine        S TCT, TCC, TCA, TCG, AGT, AGC

Tyrosine  

Y TAT, TAC
Tryptophan   W TGG
Glutamine   Q CAA, CAG
Asparagine   N AAT, AAC
Histidine 

H

CAT, CAC
Glutamic acid  

E

GAA, GAG

Aspartic acid 

D

GAT, GAC
Lysine       

K

AAA, AAG
Arginine  

R

CGT, CGC, CGA, CGG, AGA, AGG
Stop codons Stop TAA, TAG, TGA
In this table, the twenty amino acids found in proteins are listed, along
with the single-letter code used to represent these amino acids in protein data bases. The
DNA codons representing each amino acid are also listed. All 64 possible 3-letter
combinations of the DNA coding units T, C, A and G are used either to encode one of these
amino acids or as one of the three stop codons that signals the end of a sequence. While
DNA can be decoded unambiguously, it is not possible to predict a DNA sequence from its
protein sequence. Because most amino acids have multiple codons, a number of possible DNA
sequences might represent the same protein sequence.