Synonym α1-Proteinase inhibitor
Molecular mass 53.000 Da
Synthesis Liver, monocytes
Half-Life 5 days
Plasma concentration 1 - 1.3 g/l
Normal range Activity: 100%

The inhibitor is mainly responsible for the inhibition of the activity of PMN-elastase in plasma. About 90% of the elastase in plasma is inhibited by α1-antitrypsin. Although it also inhibits various other serine proteases, as e.g. thrombin, factor XIa, trypsin and activated protein C (APC), α1-antitrypsin is of no significance in the coagulation system.

Clinical significance

Reduced concentrations are observed in patients with sepsis or multi-organ failure as well as in some genetic lung and liver diseases. As an acute phase protein, increased concentrations of α1-antitrypsin can be determined is some situations. Inherited deficiency may cause liver disease and lung emphysema at an early age.


  • Control of sepsis and multi-organ failure
  • Monitoring of the elastase-inhibiting potential
  • Screening of newborns for α1-antitrypsin deficiency


  1. Friberger P. Chromogenic peptide substrates. Their use for the assay of factors in the fibrinolytic and plasma kallikrein-kinin systems. Scand J Clin Lab Invest 42, Suppl 162, 84-85, 1982.
  2. Gallimore MJ, Aurell L, Friberger P, Gustavsson S. Chromogenic peptide substrate sassys for determining functional activities of ?2-macroglobulin and α1-antitrypsin using a new trypsin substrate. Thromb Haemost 50, 230, 1983.
  3. Ohlsson K, Olsson A-S. Immunoreactive granulocyte in human serum. Hoppe-Seyler's Z Physiol Chem 359, 1531, 1978.
  4. Heck LW, Kaplan AP. Substrates of Hageman factor: I. Isolation and characterization of human factor XI (PTA) and inhibition of the activated enzyme by alpha-1-antitrypsin. J Exp Med 140, 1615, 1974.
  5. Heeb MJ, Griffin JH. Physiologic inhibition of human activated protein C by alpha-1-antitrypsin. J Biol Chem 263, 11613-11616, 1988.
  6. Sveger T, Thelin T. A future for neonatal alpha 1-antitrypsin screening? Acta Pediatr 89 (3), 259-261, 2000.
Test kits
Chromogenic Assay

UNITEST α1-Antitrypsin

Short Info Insert

Matched-Pair Antibody set

ELISA α1-Antitrypsin

Short Info Insert

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