Amino Acids

Hydrophobic amino acids

Amino acids that are nonpolar and do not interact well with water.

Examples of hydrophobic amino acids

Glycine, Alanine, Valine, Leucine, Isoleucine, Methionine, Phenylalanine, Tryptophan, Proline.

Hydrophilic (polar) amino acids

Amino acids that have side chains that are polar or can form hydrogen bonds with water.

Examples of hydrophilic amino acids

Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine.

Charged amino acids

Amino acids that have side chains that are charged either positively or negatively.

Acidic amino acids

Amino acids that are negatively charged due to the presence of an additional carboxyl group.

Examples of acidic amino acids

Aspartic acid, Glutamic acid.

Basic amino acids

Amino acids that are positively charged due to the presence of amino groups.

Examples of basic amino acids

Lysine, Arginine, Histidine.

Proline

An amino acid where the side chain is connected to the main chain, creating a cyclic structure.

Glycine

The most flexible amino acid due to its small side chain.

Aliphatic side chains

Hydrophobic side chains that include alanine, valine, isoleucine, and leucine.

Hydroxyl containing side chains

Side chains that contain -OH groups, such as serine and threonine.

Negatively charged acidic residues

Aspartate and glutamate that have a negative charge.

Basic side chains

The side chains of lysine and arginine that are positively charged.

Cysteine

An amino acid that contains a sulfhydryl group and can form disulfide bonds with other cysteine residues.

Disulfide bond

A covalent bond formed between two cysteine side chains, providing stability to proteins.

Antibodies

Proteins that have a heavy chain with two disulfide bonds and a light chain connected by a disulfide bond.

Alanine (A)

A nonpolar amino acid with a small side chain, unreactive.

Arginine (R)

A positively charged amino acid that forms ionic interactions with negatively charged groups.

Asparagine (N)

A polar, uncharged amino acid that can form hydrogen bonds.

Aspartate (D)

A negatively charged amino acid that interacts with positively charged groups.

Cysteine (C)

An amino acid with a reactive SH group that can form polar bonds.

Glutamine (Q)

A polar, uncharged amino acid that can form hydrogen bonds.

Glutamate (E)

A negatively charged amino acid commonly replacing aspartate.

Histidine (H)

An amino acid that is partially charged around pH 7, contains a C3N2H4 ring.

Isoleucine (I)

A hydrophobic, nonpolar amino acid commonly replacing valine.

Leucine (L)

A hydrophobic, nonpolar, aliphatic amino acid.

Lysine (K)

A positively charged, basic amino acid that forms ionic interactions.

Methionine (M)

A nonpolar, hydrophobic amino acid that contains sulfur.

Phenylalanine (F)

An aromatic, hydrophobic, nonreactive amino acid.

Serine (S)

A polar, uncharged amino acid that contains a hydroxyl group.

Threonine (T)

A polar, uncharged amino acid that also contains a hydroxyl group.

Tryptophan (W)

A large, hydrophobic, aromatic amino acid reactive with nitrogen.

Tyrosine (Y)

An aromatic amino acid that ionizes at pH 0 and is hydrophilic.

Valine (V)

A hydrophobic, nonpolar amino acid that is aliphatic.

Polar side chains

Side chains containing electronegative elements such as O, S, N.

Acidic residues

Amino acids with negatively charged oxygen in their side chains.

Basic residues

Amino acids with positively charged nitrogen in their side chains.