Amino Acid Code Table and Genetic Codon

Creative Peptides has long-term experience and rich professional knowledge in peptide synthesis, and provides high-quality customized peptide synthesis services, including natural and non-standard/unnatural amino acids. You can find the symbol for each natural amino acid in our reference table.

The 22 proteinogenic amino acids codes

There are approximately 20,000 unique protein-coding genes responsible for more than 100,000 unique proteins in the body. While hundreds of natural amino acids are found in nature, only about 20 amino acids are needed to make all the proteins found in the human body and most other life forms. All 20 of these amino acids are L-isomers, alpha amino acids. With the exception of glycine, they all contain chiral alpha carbon. All of these amino acids are L-isomers with an R absolute configuration, except for glycine (no chiral center) and cysteine (S absolute configuration because of the sulfur-containing R group). It is worth mentioning that selenocysteine and pyrrole lysine are considered to be the 21st and 22nd amino acids, respectively. They are recently discovered amino acids that can be incorporated into protein chains during ribosomal protein synthesis. Pyrrole lysine is functional in life; However, humans do not use pyrrole lysine in protein synthesis. After translation, these 22 amino acids can also be modified by post-translational modifications to further increase the diversity of the generated proteins.

Amino acid genetic codon table

Essential amino acid codes

Essential amino acids, also called indispensable amino acids, are amino acids that humans and other vertebrates cannot synthesize from metabolic intermediates. These amino acids must be provided from an exogenous diet because the body lacks the metabolic pathways needed to synthesize them. In nutrition, amino acids are divided into essential amino acids and non-essential amino acids. These classifications stem from early studies of human nutrition, which showed that specific amino acids are necessary for growth or nitrogen balance even when there are sufficient amounts of replacement amino acids. Although there may be differences depending on an individual's metabolic status, there are generally recognized as nine essential amino acids.

Modified and unusual amino acid codes

Phosphoserine, phosphothreonine, and phosphotyrosine are phosphorylated modifications of amino acids that are commonly used in signaling.

Hydroxyproline and 4-hydroxyproline are hydroxylated prolines that play an important role in collagen.

N-formylmethionine is a common starting amino acid in bacteria for protein synthesis.