Amino Acid Structures/Properties for BCHM 162

Glycine (Gly, G)

Glycine (Gly, G)

Achiral, no side chain, less restricted torsion angles, often found in turns

Alanine (Ala, A)

Hydrophobic/Nonpolar, Alkyl/aliphatic

Valine (Val, V)

Hydrophobic/Nonpolar, Alkyl/Aliphatic, V-shaped side chain

Leucine (Leu, L)

Hydrophobic/Nonpolar, Alkyl/Aliphatic

Isoleucine (Ile, I)

Hydrophobic/Nonpolar, Alkyl/Aliphatic

Methionine (Met, M)

Hydrophobic/Nonpolar, Alkyl/Aliphatic, Thioether

Proline (Pro, P)

Restricted torsion angles, can adopt cis peptide bond, often found in turns, Hydrophobic/Nonpolar, Alkyl/Aliphatic

Phenylalanine (Phe, F)

Aromatic (hydrophobic)

Tryptophan (Trp, W)

Aromatic (hydrophobic, polar), Absorbs UV light, Fluoresces

Tyrosine (Tyr, Y)

Aromatic (hydrophobic, polar); can be deprotonated at physiological pH since pKa - 10; can be phosphorylated

Serine (Ser, S)

Polar, Uncharged, Hydroxyl group can be phosphorylated or glycosylated

Threonine (Thr, T)

Polar, Uncharged, Hydroxyl group can be phosphorylated or glycosylated

Asparagine (Asn, N)

Polar, Uncharged, Amide can be glycosylated

Glutamine (Gln, Q)

Polar, Uncharged, can cross-link with Lys via isopeptide bond

Cysteine (Cys, C)

(Polar, Uncharged) Thiol/sulfhydryl can lose a proton at physiological pH (pKa ~8), Reactive: can form disulfide bonds or be oxidized to sulfonic acid

Histidine (His, H)

Proton shuttle at physiological pH (pKa ~6) (Hydrophilic, Positively Charged, Aromatic)

Lysine (Lys, K)

Basic, Positively Charged at physiological pH (pKa ~10), primary amine (has both hydrophilic and hydrophobic regions of the side chain)

Arginine (Arg, R)

Basic, Positively Charged at physiological pH (pKa ~12)

Aspartate (Asp, D)

Acidic, Negatively Charged at physiological pH, Carboxylate (pKa ~4)

Glutamate (Glu, E)

Acidic, Negatively Charged at physiological pH, Carboxylate (pKa ~4)