In enzymology, a L,L-diaminopimelate aminotransferase (EC 2.6.1.83) is an enzyme that catalyzes the chemical reaction

LL-2,6-diaminoheptanedioate + 2-oxoglutarate (S)-2,3,4,5-tetrahydropyridine-2,6-dicarboxylate + L-glutamate + H₂O

Thus, the two substrates of this enzyme are LL-2,6-diaminoheptanedioate and 2-oxoglutarate, whereas its 3 products are (S)-2,3,4,5-tetrahydropyridine-2,6-dicarboxylate, L-glutamate, and H₂O.

This enzyme belongs to the family of transferases, specifically the transaminases, which transfer nitrogenous groups. The systematic name of this enzyme class is LL-2,6-diaminoheptanedioate:2-oxoglutarate aminotransferase. Other names in common use include LL-diaminopimelate transaminase, LL-DAP aminotransferase, and LL-DAP-AT. This enzyme participates in lysine biosynthesis.

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 2Z1Z and 2Z20.

• Hudson AO, Singh BK, Leustek T, Gilvarg C (2006). "An LL-diaminopimelate aminotransferase defines a novel variant of the lysine biosynthesis pathway in plants". Plant Physiol. 140 (1): 292–301. doi:10.1104/pp.105.072629. PMC 1326051. PMID 16361515.