Neutrophil and pancreatic elastase-specific inhibitor of skin. It may prevent elastase-mediated tissue proteolysis. Has been shown to inhibit the alpha-4-beta-2/CHRNA2-CHRNB2 nicotinic acetylcholine receptor and to produce a weak inhibition on Kv11.1/KCNH2/ERG1 and on the transient receptor potential cation channel subfamily V member 1 (TRPV1) (PubMed:29483648). . This is the function of PI3 (peptidase inhibitor 3, ENSG00000124102).