The enzyme erythro-3-hydroxyaspartate ammonia-lyase (EC 4.3.1.20) catalyzes the chemical reaction
This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is erythro-3-hydroxy-<small>L</small>-aspartate ammonia-lyase (oxaloacetate-forming). Other names in common use include erythro-ò-hydroxyaspartate dehydratase, erythro-3-hydroxyaspartate dehydratase, erythro-3-hydroxy-<small>L</small><sub>s</sub>-aspartate hydro-lyase (deaminating); erythro-3-hydroxy-<small>L</small><sub>s</sub>-aspartate ammonia-lyase. It employs one cofactor, pyridoxal phosphate.