<small>L</small>-lysine cyclodeaminase (EC 4.3.1.28, rapL (gene), fkbL (gene), tubZ (gene), visC (gene)) is an enzyme with systematic name <small>L</small>-lysine ammonia-lyase (cyclizing; ammonia-forming). This enzyme catalyses the following chemical reaction
This enzyme requires bound NAD<sup>+</sup>.