Amino Acid

Amino acids are the building blocks of peptides and proteins. The specific sequence of amino acids determines a peptide’s structure and biological activity.

Each standard amino acid shares a common backbone — a central alpha carbon bonded to an amino group, a carboxyl group, and a hydrogen atom — and differs only in its variable side chain, or R group. The chemistry of that side chain, whether hydrophobic, polar, or charged, drives how a peptide folds and how it interacts with its molecular targets.

Twenty proteinogenic amino acids make up most natural sequences, but research peptides frequently incorporate non-standard or modified residues, such as aminoisobutyric acid (Aib) or D-amino acids, to resist enzymatic cleavage and improve stability in in-vitro assays.