The formula of an amino acid comprises, bound to a carbon (alpha carbon):
Chemically speaking, an amino acid is a carboxylic acid which has an amine group attached to it. The general linear formula of an amino acid is R-CH(NH2)-COOH.
The 20 common amino acids are grouped in classes according to their side chains:
Click here for IMGT classes of the 20 common amino acids 'Physicochemical' properties.
POLAR SIDE CHAINS | NON POLAR SIDE CHAINS | ||
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SERINE | ![]() |
GLYCINE | ![]() |
THREONINE | ![]() | ALANINE | ![]() |
TYROSINE | ![]() |
CYSTEINE (1) | ![]() |
ASPARAGINE | ![]() |
VALINE | ![]() |
GLUTAMINE | ![]() |
LEUCINE | ![]() |
ISOLEUCINE | ![]() | ||
PROLINE | ![]() | ||
METHIONINE | ![]() | ||
PHENYLALANINE | ![]() | ||
TRYPTOPHAN | ![]() |
Charged side chains are POLAR.
ACIDIC SIDE CHAINS | BASIC SIDE CHAINS | ||
---|---|---|---|
ASPARTIC ACID |
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LYSINE |
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GLUTAMIC ACID |
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ARGININE |
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HISTIDINE |
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Amino acid | Abbreviations | Molecular formula | Linear formula | |
---|---|---|---|---|
Alanine | Ala | A | C3H7NO2 | CH3-CH(NH2)-COOH |
Arginine | Arg | R | C6H14N4O2 | HN=C(NH2)-NH-(CH2)3-CH(NH2)-COOH |
Asparagine | Asn | N | C4H8N2O3 | H2N-CO-CH2-CH(NH2)-COOH |
Aspartic acid | Asp | D | C4H7NO4 | HOOC-CH2-CH(NH2)-COOH |
Cysteine | Cys | C | C3H7NO2S | HS-CH2-CH(NH2)-COOH |
Glutamine | Gln | Q | C5H10N2O3 | H2N-CO-(CH2)2-CH(NH2)-COOH |
Glutamic acid | Glu | E | C5H9NO4 | HOOC-(CH2)2-CH(NH2)-COOH |
Glycine | Gly | G | C2H5NO2 | NH2-CH2-COOH |
Histidine | His | H | C6H9N3O2 | NH-CH=N-CH=C-CH2-CH(NH2)-COOH |
Isoleucine | Ile | I | C6H13NO2 | CH3-CH2-CH(CH3)-CH(NH2)-COOH |
Leucine | Leu | L | C6H13NO2 | (CH3)2-CH-CH2-CH(NH2)-COOH |
Lysine | Lys | K | C6H14N2O2 | H2N-(CH2)4-CH(NH2)-COOH |
Methionine | Met | M | C5H11NO2S | CH3-S-(CH2)2-CH(NH2)-COOH |
Phenylalanine | Phe | F | C9H11NO2 | Ph-CH2-CH(NH2)-COOH |
Proline | Pro | P | C5H9NO2 | NH-(CH2)3-CH-COOH |
Serine | Ser | S | C3H7NO3 | HO-CH2-CH(NH2)-COOH |
Threonine | Thr | T | C4H9NO3 | CH3-CH(OH)-CH(NH2)-COOH |
Tryptophan | Trp | W | C11H12N2O2 | Ph-NH-CH=C-CH2-CH(NH2)-COOH |
Tyrosine | Tyr | Y | C9H11NO3 | HO-Ph-CH2-CH(NH2)-COOH |
Valine | Val | V | C5H11NO2 | (CH3)2-CH-CH(NH2)-COOH |
The general formula of an amino acid is composed by a carbon alpha atom, a carboxyl group, a side chain group and an amino group.
AMINO ACID | MOLECULAR FORMULA | 3D MOLECULAR MODEL | ATOMS NOMENCLATURE |
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ALANINE | ![]() |
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ARGININE | ![]() |
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ASPARAGINE | ![]() |
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ASPARTIC ACID | ![]() |
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CYSTEINE | ![]() |
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GLUTAMINE | ![]() |
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GLUTAMIC ACID | ![]() |
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GLYCINE | ![]() |
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HISTIDINE | ![]() |
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ISOLEUCINE | ![]() |
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LEUCINE | ![]() |
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LYSINE | ![]() |
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METHIONINE | ![]() |
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PHENYLALANINE | ![]() |
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PROLINE | ![]() |
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SERINE | ![]() |
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THREONINE | ![]() |
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TRYPTOPHAN | ![]() |
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TYROSINE | ![]() |
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VALINE | ![]() |
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