Catalyzes the activation of alpha-aminoadipate by ATP-dependent adenylation and the reduction of activated alpha-aminoadipate by NADPH. The activated alpha-aminoadipate is bound to the phosphopantheinyl group of the enzyme itself before it is reduced to (S)-2-amino-6-oxohexanoate. (S)-2-amino-6-oxohexanoate + H2O + NADP(+) = 2 H(+) + L-2-aminoadipate + NADPH (S)-2-amino-6-oxohexanoate + H2O + NAD(+) = 2 H(+) + L-2-aminoadipate + NADH (S)-2-amino-6-oxohexanoate + AMP + diphosphate + NADP(+) = ATP + H(+) + L-2-aminoadipate + NADPH Binds 1 phosphopantetheine covalently. Amino-acid biosynthesis; L-lysine biosynthesis via AAA pathway; L-lysine from L-alpha-aminoadipate (fungal route): step 1/3. Belongs to the ATP-dependent AMP-binding enzyme family.