Amino Acid and Codon Table
Table of standard amino acid abbreviations and properties
| Amino Acid | 3-Letter[94] | 1-Letter[94] | Side-chain polarity[94] | Side-chain charge (pH 7.4)[94] | Hydropathy index[95] | Absorbance λmax(nm)[96] | ε at λmax (x10−3 M−1 cm−1)[96] |
|---|---|---|---|---|---|---|---|
| Aspartic acid | Asp | D | polar | negative | −3.5 | ||
| Glutamic acid | Glu | E | polar | negative | −3.5 | ||
| Asparagine | Asn | N | polar | neutral | −3.5 | ||
| Cysteine | Cys | C | polar | neutral | 2.5 | 250 | 0.3 |
| Alanine | Ala | A | nonpolar | neutral | 1.8 | ||
| Glutamine | Gln | Q | polar | neutral | −3.5 | ||
| Glycine | Gly | G | nonpolar | neutral | −0.4 | ||
| Isoleucine | Ile | I | nonpolar | neutral | 4.5 | ||
| Leucine | Leu | L | nonpolar | neutral | 3.8 | ||
| Methionine | Met | M | nonpolar | neutral | 1.9 | ||
| Phenylalanine | Phe | F | nonpolar | neutral | 2.8 | 257, 206, 188 | 0.2, 9.3, 60.0 |
| Proline | Pro | P | nonpolar | neutral | −1.6 | ||
| Serine | Ser | S | polar | neutral | −0.8 | ||
| Threonine | Thr | T | polar | neutral | −0.7 | ||
| Tryptophan | Trp | W | nonpolar | neutral | −0.9 | 280, 219 | 5.6, 47.0 |
| Tyrosine | Tyr | Y | polar | neutral | −1.3 | 274, 222, 193 | 1.4, 8.0, 48.0 |
| Valine | Val | V | nonpolar | neutral | 4.2 | ||
| Arginine | Arg | R | polar | positive | −4.5 | ||
| Lysine | Lys | K | polar | positive | −3.9 | ||
| Histidine | His | H | polar | positive(10%)
neutral(90%) |
−3.2 | 211 | 5.9 |
In addition, there are two additional amino acids that are incorporated by overriding stop codons:
| 21st and 22nd amino acids | 3-Letter | 1-Letter |
|---|---|---|
| Selenocysteine | Sec | U |
| Pyrrolysine | Pyl | O |
In addition to the specific amino acid codes, placeholders are used in cases where chemical or crystallographic analysis of a peptide or protein cannot conclusively determine the identity of a residue.
| 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 | X |
Unk is sometimes used instead of Xaa, but is less standard.
In addition, many non-standard amino acids have a specific code. For example, several peptide drugs, such as Bortezomib and MG132, are artificially synthesized and retain their protecting groups, which have specific codes. Bortezomib is Pyz-Phe-boroLeu, and MG132 is Z-Leu-Leu-Leu-al. To aid in the analysis of protein structure, photocrosslinking amino acid analogues are available. These include photoleucine (pLeu) and photomethionine (pMet).[97]
RNA codon table
| nonpolar | polar | basic | acidic | (stop codon) |
| 2nd base | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| U | C | A | G | ||||||
| 1st base | U | UUU | (Phe/F) Phenylalanine | UCU | (Ser/S) Serine | UAU | (Tyr/Y) Tyrosine | UGU | (Cys/C) Cysteine |
| UUC | (Phe/F) Phenylalanine | UCC | (Ser/S) Serine | UAC | (Tyr/Y) Tyrosine | UGC | (Cys/C) Cysteine | ||
| UUA | (Leu/L) Leucine | UCA | (Ser/S) Serine | UAA | Stop (Ochre) | UGA | Stop (Opal) | ||
| UUG | (Leu/L) Leucine | UCG | (Ser/S) Serine | UAG | Stop (Amber) | UGG | (Trp/W) Tryptophan | ||
| C | CUU | (Leu/L) Leucine | CCU | (Pro/P) Proline | CAU | (His/H) Histidine | CGU | (Arg/R) Arginine | |
| CUC | (Leu/L) Leucine | CCC | (Pro/P) Proline | CAC | (His/H) Histidine | CGC | (Arg/R) Arginine | ||
| CUA | (Leu/L) Leucine | CCA | (Pro/P) Proline | CAA | (Gln/Q) Glutamine | CGA | (Arg/R) Arginine | ||
| CUG | (Leu/L) Leucine | CCG | (Pro/P) Proline | CAG | (Gln/Q) Glutamine | CGG | (Arg/R) Arginine | ||
| A | AUU | (Ile/I) Isoleucine | ACU | (Thr/T) Threonine | AAU | (Asn/N) Asparagine | AGU | (Ser/S) Serine | |
| AUC | (Ile/I) Isoleucine | ACC | (Thr/T) Threonine | AAC | (Asn/N) Asparagine | AGC | (Ser/S) Serine | ||
| AUA | (Ile/I) Isoleucine | ACA | (Thr/T) Threonine | AAA | (Lys/K) Lysine | AGA | (Arg/R) Arginine | ||
| AUG[A] | (Met/M) Methionine | ACG | (Thr/T) Threonine | AAG | (Lys/K) Lysine | AGG | (Arg/R) Arginine | ||
| G | GUU | (Val/V) Valine | GCU | (Ala/A) Alanine | GAU | (Asp/D) Aspartic acid | GGU | (Gly/G) Glycine | |
| GUC | (Val/V) Valine | GCC | (Ala/A) Alanine | GAC | (Asp/D) Aspartic acid | GGC | (Gly/G) Glycine | ||
| GUA | (Val/V) Valine | GCA | (Ala/A) Alanine | GAA | (Glu/E) Glutamic acid | GGA | (Gly/G) Glycine | ||
| GUG | (Val/V) Valine | GCG | (Ala/A) Alanine | GAG | (Glu/E) Glutamic acid | GGG | (Gly/G) Glycine | ||
- A The codon AUG both codes for methionine and serves as an initiation site: the first AUG in an mRNA‘s coding region is where translation into protein begins.[30]
| Ala/A | GCU, GCC, GCA, GCG | Leu/L | UUA, UUG, CUU, CUC, CUA, CUG |
|---|---|---|---|
| Arg/R | CGU, CGC, CGA, CGG, AGA, AGG | Lys/K | AAA, AAG |
| Asn/N | AAU, AAC | Met/M | AUG |
| Asp/D | GAU, GAC | Phe/F | UUU, UUC |
| Cys/C | UGU, UGC | Pro/P | CCU, CCC, CCA, CCG |
| Gln/Q | CAA, CAG | Ser/S | UCU, UCC, UCA, UCG, AGU, AGC |
| Glu/E | GAA, GAG | Thr/T | ACU, ACC, ACA, ACG |
| Gly/G | GGU, GGC, GGA, GGG | Trp/W | UGG |
| His/H | CAU, CAC | Tyr/Y | UAU, UAC |
| Ile/I | AUU, AUC, AUA | Val/V | GUU, GUC, GUA, GUG |
| START | AUG | STOP | UAA, UGA, UAG |