PiL, or Serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 2 (gene/pseudogene), is a human gene encoded by SERPINA2. It may also be known as: Putative alpha-1-antitrypsin-related protein; Serpin A2; Protease inhibitor 1-like; protease inhibitor 1 (alpha-1-antitrypsin)-like; ARGS; PIL; SERPINA2P; psiATR. The encoded protein has an amino acid length of 420 and a mass of 47.9 kDa. PiL is a member of the Serpin family. Homologs of this gene exist in other organisms, including: Mouse.