Serine (or cysteine) proteinase inhibitor clade A (alpha 1 antiproteinase, antitrypsin) member 3
Serine (or cysteine) proteinase inhibitor clade A member 3
Serine proteinase inhibitor clade A member 3
Serpin family A member 3
Serpin peptidase inhibitor clade A (alpha 1 antiproteinase antitrypsin) member 3
FunctionAlthough its physiological function is unclear, it can inhibit neutrophil cathepsin G and mast cell chymase, both of which can convert angiotensin-1 to the active angiotensin-2.
Tissue specificityPlasma. Synthesized in the liver. Like the related alpha-1-antitrypsin, its concentration increases in the acute phase of inflammation or infection. Found in the amyloid plaques from the hippocampus of Alzheimer disease brains.
Involvement in diseaseDefects in SERPINA3 may be a cause of chronic obstructive pulmonary disease (COPD) [MIM:107280].
Sequence similaritiesBelongs to the serpin family.
DomainThe reactive center loop (RCL) extends out from the body of the protein and directs binding to the target protease. The protease cleaves the serpin at the reactive site within the RCL, establishing a covalent linkage between the carboxyl group of the serpin reactive site and the serine hydroxyl of the protease. The resulting inactive serpin-protease complex is highly stable.