Alpha-1-antitrypsin is an alias for the gene, Serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 1, in humans. Other names include: Alpha-1-antitrypsin; Alpha-1-antiproteinase; Serpin A1; Alpha-1 protease inhibitor; protease inhibitor 1 (anti-elastase), alpha-1-antitrypsin; A1A; A1AT; AAT; PI; PI1; PRO2275; alpha1AT. The encoded protein has an amino acid length of 418 and a mass of 46.7 kDa. Alpha-1-antitrypsin is a member of the Serpin family. This gene shares homology with other species, including: Mouse.