meso-α,ε-Diaminopimelic acid is the last intermediate in the biosynthesis of lysine and undergoes decarboxylation by diaminopimelate decarboxylase to give the final product.

[1] DAP is a characteristic of certain cell walls[2] of some bacteria.

DAP is often found in the peptide linkages of NAM-NAG chains that make up the cell wall of gram-negative bacteria.

When in deficiency, they still grow but with the inability to make new cell wall peptidoglycan.

This is also the attachment point for Braun's lipoprotein.