 It also localizes to Neutrophil extracellular traps (NETs), via its high affinity for DNA, an unusual property for serine proteases.As with other serine proteinases it contains a charge relay system composed of the catalytic triad of histidine, aspartate, and serine residues that are dispersed throughout the primary sequence of the polypeptide but that are brought together in the three dimensional conformation of the folded protein.The gene encoding neutrophil elastase, ELA2, consists of five exons.