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Definition: A glycoprotein that is the major protease inhibitor of human serum, is synthesized in the liver, and is genetically polymorphic due to the presence of 25 alleles; people appropriately homozygous are deficient in α1-antitrypsin and are predisposed to pulmonary emphysema and juvenile hepatic cirrhosis because of alterations in the amino acid and sialic acid components of the glycoprotein. The concentration of α1-antitrypsin increases in response to injury or infection. α1-Antitrypsin also inhibits thrombin and elastase.

Synonym(s): α1-antitrypsin inhibitor, human α1-protease inhibitor

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.