The SERPINA1 gene (SERPINA1 stands for "Serine (or Cysteine) Proteinase Inhibitor, Clade A (Alpha-1 Antiproteinase, Antitrypsin), Member" is a protein coding gene located on chromosome 14q32.13. The protein encoded by this gene is a serine protease inhibitor that belongs to the serpin superfamily, whose targets include elastase, plasmin, thrombin, trypsin, chymotrypsin, and plasminogen activator. Inhibitor of serine proteases. Several transcript variants encoding the same protein have been found for this gene.
The serine protease inhibitor SERPINA1 is produced in the liver, bone marrow, lymphocytic and monocytic cells in lymphoid tissue, and Paneth cells of the intestine. The main target of serine protease inhibitor A1 is elastase. Its main physiological function is to protect the lower respiratory tract from proteolytic destruction by human leukocyte elastase. The enzyme also has moderate affinity for plasmin and thrombin. The aberrant form inhibits insulin-induced NO synthesis in platelets, shortens clotting time, and has proteolytic activity toward insulin and plasmin.