Diaminopimelic acid or DAPA is a lysine-like amino acid derivative that is a key component of the bacterial cell wall. DAPA is incorporated or integrated into peptidoglycan of gram negative bacteria and is the attachment point for Braun's lipoprotein (BLP or Murein Lipoprotein). BLP is found in gram-negative cell walls and is one of the most abundant membrane proteins.

The rhizomes of Atractylodes macrocephala Koidz.

This is a class I (Kb)-restricted peptide epitope of OVA, an octameric peptide from ovalbumin presented by the class I MHC molecule, H-2Kb.