Amino Acids Chart
Amino acids are the building blocks of p roteins, and are essential for many functions in the human body. There are 22 different amino acids that make up the proteins in our body, each with its own unique properties and functions.
Amino Acids Chart
One way to visualize the different amino acids is through an amino acid chart. This chart displays the different amino acids in a grid format, with each row representing a different amino acid and columns showing information such as the amino acid’s structure, abbreviation, and properties.
The body produces alanine, abbreviated as Ala, on its own as it is a non-essential amino acid with the structure H2N-CH3-COOH.
Lysine, abbreviated as Lys, is an essential amino acid that must be obtained through diet, as it has the structure H2N-CH2-CH2-CH2-CH2-CH2-NH2.
The amino acid alanine is produced by the body, as it is non-essential with the structure H2N-CH3-COOH. To obtain the essential amino acid lysine, one must include it in their diet as it has the structure H2N-CH2-CH2-CH2-CH2-CH2-NH2.
Amino Acid Chart
| Amino Acid | Abb | Molecular Weight | Molecular Formula | Residue Formula | Residue Weight | pKa1 value | pKb2 value | pKx3 value | pI4 value |
| Alanine | Ala | 89.09 | C3H7NO2 | CH3COOH | 75.07 | 2.35 | 9.87 | – | 6.01 |
| Arginine | Arg | 174.2 | C6H14N4O2 | NH2CH(NH2)COOH | 156.18 | 2.17 | 9.04 | 12.48 | 10.76 |
| Asparagine | Asn | 132.12 | C4H8N2O3 | NH2C(O)NH2 | 114.08 | 2.02 | 8.8 | – | 5.41 |
| Aspartic Acid | Asp | 133.1 | C4H7NO4 | COOHCH(NH2) | 133.1 | 1.88 | 9.6 | – | 2.77 |
| Cysteine | Cys | 121.16 | C3H7NO2S | CH3S-COOH | 103.12 | 1.96 | 10.28 | – | 5.07 |
| Glutamic Acid | Glu | 147.13 | C5H9NO4 | COOHCH2CH(NH2) | 129.06 | 2.19 | 9.67 | – | 3.22 |
| Glutamine | Gln | 146.14 | C5H10N2O3 | NH2C(O)CH2CH(NH2) | 128.11 | 2.17 | 9.13 | – | 5.65 |
| Glycine | Gly | 75.07 | C2H5NO2 | NH2CH2COOH | 57.03 | 2.35 | 9.78 | – | 6.06 |
| Histidine | His | 155.16 | C6H9N3O2 | NH2CH(NH2)CH2COOH | 137.14 | 1.8 | 8.97 | 6.04 | 7.59 |
| Hydroxyproline | Hyp | 131.17 | C9H11NO3 | CH2OH(CH(OH)CH2)COOH | 113.13 | – | – | – | – |
| Isoleucine | Ile | 131.18 | C6H13NO2 | CH3CH2CH(CH3)COOH | 113.15 | 2.36 | 9.76 | – | 6.05 |
| Leucine | Leu | 131.18 | C6H13NO2 | CH3CH2CH(CH3)COOH | 113.15 | 2.36 | 9.76 | – | 6.05 |
| Lysine | Lys | 146.19 | C6H14N2O2 | NH2CH2CH2CH2CH2COOH | 128.17 | 2.18 | 8.95 | 10.53 | 9.74 |
| Methionine | Met | 149.21 | C5H11NO2S | CH3SCH2COOH | 131.19 | 2.13 | 9.28 | – | 5.74 |
| Phenylalanine | Phe | 165.19 | C9H11NO2 | C6H5CH2COOH | 147.13 | 2.2 | 9.13 | – | 5.48 |
| Proline | Pro | 115.13 | C5H9NO2 | CH2CH(NH2)COOH | 97.11 | 2 | 10.64 | – | 6.3 |
| Pyroglutamatic | Pyl | 129.11 | C5H7NO3 | NH2C(=O)COOH | 113.09 | 2.17 | 8.28 | – | 5.99 |
| Serine | Ser | 105.09 | C3H7NO3 | CH2OHCOOH | 89.07 | 2.19 | 9.15 | – | 5.68 |
| Threonine | Thr | 119.12 | C4H9NO3 | CH3CH(OH)COOH | 103.1 | 2.09 | 9.1 | – | 5.6 |
| Tryptophan | Trp | 204.23 | C11H12N2O2 | CH(NH)C6H5COOH | 186.17 | 2.38 | 9.41 | – | 5.89 |
| Tyrosine | Tyr | 181.19 | C9H11NO3 | C6H4OHCOOH | 165.17 | 2.2 | 9.11 | – | 5.66 |
| Valine | Val | 117.15 | C5H11NO2 | CH3CH2CH(NH2)COOH | 99.13 | 2.29 | 9.74 | – | 6 |
The classification of amino acids as polar or non-polar plays a crucial role in determining the structure and function of proteins. Polar amino acids, with their polar side chains, tend to be hydrophilic and attract water. On the other hand, non-polar amino acids, with their non-polar side chains, tend to be hydrophobic and repel water.
Structure
The structure of an amino acid is composed of a central carbon atom, known as the alpha carbon, bonded to a carboxyl group, an amino group, a hydrogen atom, and a side chain, known as the R group. The R group is unique to each amino acid and is responsible for the different properties and functions of each amino acid.
Types of Amino Acids
The 22 common amino acids can be classified into several categories based on their properties and functions. The four main categories are:
- Nonpolar, hydrophobic amino acids, such as alanine, valine, and leucine. These amino acids are not attracted to water and tend to be found in the interior of proteins.
- Polar, hydrophilic amino acids, such as serine, threonine, and tyrosine. These amino acids are attracted to water and tend to be found on the surface of proteins.
- Acidic amino acids, such as aspartic acid and glutamic acid. These amino acids have a carboxyl group and a negative charge at neutral pH.
- Basic amino acids, such as arginine and lysine. These amino acids have an amino group and a positive charge at neutral pH.
Classification by function
Amino acids can also be classified based on their biological functions. Some amino acids are essential, meaning that they cannot be synthesized by the body and must be obtained from dietary sources. Others are nonessential, meaning that they can be synthesized by the body.
The amino acids and their abbreviation
Biochemists and molecular biologists use a single letter code to abbreviate amino acids, using the first letter of the amino acid’s name. For example, they abbreviate Alanine as A, Aspartic acid as D, and Glutamic acid as E. These abbreviations are used in protein, peptide, and biomolecule sequences, as well as in genetic code and amino acid numbering systems to identify specific positions in a protein sequence.
Alanine (Ala)
Arginine (Arg)
Asparagine (Asn)
Aspartic acid (Asp)
Cysteine (Cys)
Glutamic acid (Glu)
Glutamine (Gln)
Glycine (Gly)
Histidine (His)
Isoleucine (Ile)
Leucine (Leu)
Lysine (Lys)
Methionine (Met)
Phenylalanine (Phe)
Proline (Pro)
Serine (Ser)
Threonine (Thr)
Tryptophan (Trp)
Tyrosine (Tyr)
Valine (Val)