Involved in the lysine biosynthetic pathways. It catalyzes the transfer of an amino group from L-glutamate to N-succinyl-2-l-amino-6-oxoheptanedioate (N-succinyl-2-l-amino-6-ketopimelate) in a PLP-dependent reaction, yielding as products N-succinyl-l-2,6-diaminoheptanedioate (N-succinyl-diaminopimelate) and 2-oxoglutarate (Probable). 2-oxoglutarate + N-succinyl-(2S,6S)-2,6-diaminoheptanedioate = (S)-2-succinylamino-6-oxoheptanedioate + L-glutamate Binds 1 pyridoxal phosphate per subunit. Amino-acid biosynthesis; L-lysine biosynthesis via DAP pathway; LL-2,6-diaminopimelate from (S)-tetrahydrodipicolinate (succinylase route): step 2/3. Homodimer. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family.