Catalyzes the transfer of the alpha-amino group from L-lysine to 7-keto-8-aminopelargonic acid (KAPA) to form 7,8-diaminopelargonic acid (DAPA). B.subtilis is the only bacterium known to utilize L-lysine as an amino donor in the biosynthesis of DAPA. (8S)-8-amino-7-oxononanoate + L-lysine = (7R,8S)-7,8-diammoniononanoate + (S)-2-amino-6-oxohexanoate Inhibited by 7-keto-8-aminopelargonic acid at concentrations above 80 uM. Optimum pH is 8.6. Cofactor biosynthesis; biotin biosynthesis; 7,8-diaminononanoate from 8-amino-7-oxononanoate (Lys route). Homodimer. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family. BioA subfamily.