Lysine 6 dehydrogenase

Lysine 6-dehydrogenase (EC 1.4.1.18, L-lysine epsilon-dehydrogenase, L-lysine 6-dehydrogenase, LysDH) is an enzyme with systematic name L-lysine:NAD⁺ 6-oxidoreductase (deaminating). This enzyme catalyses the following chemical reaction

L-lysine + NAD⁺ ⇌ (S)-2,3,4,5-tetrahydropyridine-2-carboxylate + NADH + H⁺ + NH₃ (overall reaction) (1a) L-lysine + NAD⁺ + H₂O ⇌ (S)-2-amino-6-oxohexanoate + NADH + H⁺ + NH₃ (1b) (S)-2-amino-6-oxohexanoate ⇌ (S)-2,3,4,5-tetrahydropyridine-2-carboxylate + H₂O (spontaneous)

The enzyme is highly specific for L-lysine as substrate, although S-(2-aminoethyl)-L-cysteine can act as a substrate, but more slowly.