Neutrophil elastase is a serine protease in the same family as chymotrypsin and has broad substrate specificity. Secreted by neutrophils during inflammation, it destroys bacteria and host tissue. As with other serine proteases 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 dimension conformation of the folded protein. The gene encoding neutrophil elastase, ELA2, consists of five exons.  The neutrophil form of elastase is 218 amino acids long, with two asparagine-linked carbohydrate chains. It is present in azurophil granules in the neutrophil cytoplasm. There appear to be two forms of neutrophil elastase, termed IIa and IIb.