Amino acids

Glycine (Gly, G)

Smallest amino acid with hydrogen as its side chain; flexible and often found in protein turns and loops.

Alanine (Ala, A)

Amino acid with a methyl group (-CH₃) side chain; hydrophobic and found in protein interiors.

Valine (Val, V)

Branched-chain amino acid with an isopropyl group; hydrophobic and contributes to protein stability.

Leucine (Leu, L)

Branched-chain amino acid with an isobutyl group; essential for muscle building and hydrophobic.

Isoleucine (Ile, I)

Branched-chain amino acid with a sec-butyl group; essential and contributes to protein stability.

Proline (Pro, P)

Cyclic amino acid with a unique ring structure; causes kinks in protein chains and found in turns and loops.

Methionine (Met, M)

Sulfur-containing amino acid with a thioether group; hydrophobic and initiator for protein synthesis.

Phenylalanine (Phe, F)

Aromatic amino acid with a benzyl group; hydrophobic and important for protein stability.

Tyrosine (Tyr, Y)

Aromatic amino acid with a phenolic group; can form hydrogen bonds and is a precursor to neurotransmitters.

Tryptophan (Trp, W)

Aromatic amino acid with an indole ring; hydrophobic and a precursor to serotonin.

Serine (Ser, S)

Hydroxyl-containing amino acid with a hydroxymethyl group; can form hydrogen bonds and involved in enzyme active sites.

Threonine (Thr, T)

Hydroxyl-containing, essential amino acid with a branched chain; can form hydrogen bonds and found on protein surfaces.

Cysteine (Cys, C)

Sulfur-containing amino acid with a thiol group; forms disulfide bonds and important in protein folding.

Asparagine (Asn, N)

Amide-containing amino acid with an amide group; can form hydrogen bonds and often found in protein surfaces.

Glutamine (Gln, Q)

Amide-containing amino acid with an amide group; can form hydrogen bonds and important for nitrogen metabolism.

Aspartic Acid (Asp, D)

Acidic amino acid with a carboxyl group; negatively charged at physiological pH and involved in enzyme active sites.

Glutamic Acid (Glu, E)

Acidic amino acid with a carboxyl group; negatively charged at physiological pH and important in neurotransmission.

Lysine (Lys, K)

Basic amino acid with an amino group; positively charged at physiological pH and essential for collagen cross-linking.

Arginine (Arg, R)

Basic amino acid with a guanidinium group; positively charged at physiological pH and important in nitric oxide synthesis.

Histidine (His, H)

Basic, aromatic amino acid with an imidazole ring; can act as both proton donor and acceptor, important in enzyme active sites.

Selenocysteine (Sec, U)

Rare selenium-containing amino acid with a thiol group; essential for redox reactions in certain enzymes.

Pyrrolysine (Pyl, O)

Rare amino acid with a pyrroline ring; found in certain archaea and bacteria, used in methyltransferases.