Alpha 1-Antitrypsin, human
Description of Alpha 1-Antitrypsin
Alpha 1Antitrypsin (Î±1AT), also known as Alpha 1Proteinase inhibitor (Î±1PI), is the most abundant protease inhibitor in blood and a member of the SERPIN family of proteinase inhibitors. Serum levels are typically 1.3 mg/ml (25 Î¼M) but Î±1AT is an acute phase protein and concentrations can rise four-fold during inflammatory episodes or tissue injury. Low levels in circulation have been associated with pulmonary disease such as emphysema. Î±1AT is a single chain molecule with a mass of 52,000 daltons that is produced primarily in the liver and to a lesser extent by blood monocytes and intestinal epithelium. Based on association rates, the primary target enzyme for Î±1AT is believed to be neutrophil elastase1,2, but Î±1AT is a broad-spectrum inhibitor for many serine proteinases and the main role of Î±1AT in vivo is likely that of a â€œbackupâ€ inhibitor and proteinase scavenger in fluids and tissues. Although the association rates of Î±1AT with other enzymes are lower, the high concentration in plasma makes it an important inhibitor of activated Protein C, activated FXI, thrombin and plasmin1-4. Enzyme inhibition by Î±1AT occurs through proteolytic cleavage between Met358 and Ser359, which induces a conformational change in Î±1AT locking the enzyme into a stable, inactive 1:1 enzyme-inhibitor complex.
1. Johnson D, Travis J; Oxidative Inactivation of Human Î±-1-Proteinase Inhibitor; JBC 254, pp4022-4026, 1979.
2. Travis J, Johnson D; Human Î±-1-Proteinase Inhibitor; Methods in Enzymology, 80, pp 754-765, 1981.
3. Heeb MJ, Griffin JH; Physiologic Inhibition of Human Activated Protein C by Î±-1-Trypsin Inhibitor; JBC 263, pp11613-11616, 1988.
4. Scott CF, Schapira M, James HL, Cohen AB, Colman RW; The Inactivation of Factor XIa by plasma protease inhibitors: Predominant role of Î±1protease inhibitor and protective effect of high molecular weight kininogen. J Clin Invest 69, pp 844, 1982.
GA1AT-IG Goat anti-human Î±1AT, whole IgG from antiserum
SA1AT-IG Sheep anti-human Î±1AT, whole IgG from antiserum
SA1AT-AP Sheep anti-human Î±1AT, affinity purified IgG
SA1AT-APHRP Sheep anti-human Î±1AT, APIgG-peroxidase
A1AT-EIA Paired antibody set for ELISA of Î±1AT , 5 x 96 wells
APCAT-EIA Paired antibody set for ELISA of APC-Î±1AT complexes