Human Serpin A3/ alpha1-Antichymotrypsin Antibody

Serpin A3 is a member of the Serpin superfamily of the serine protease inhibitors (1). It is synthesized primarily in the liver and secreted as one of the most abundant serpins in plasma (2). It is known to inhibit several serine proteases including chymotrypsin, cathepsin G, chymase, kallikrein 3/prostate specific antigen, and unidentified ectoenzymes that process pro-macrophage stimulating protein (1‑5). Serpin A3 is a major constituent of the plaques associated with Alzheimer’s disease and an inhibitor of amyloid beta peptide degradation (1‑6). Deficiency in Serpin A3 activity due to a point mutation (Leu55Pro) is associated with chronic obstructive pulmonary disease (7). Human Serpin A3 is synthesized as a 423 amino acid precursor (8, 9). The mature protein is secreted and has two forms that differ in their N‑termini (10). One of the forms starting at Asn26 was expressed and purified.