Proteins

Proteins, proteomics

alpha 1-antichymotrypsin

alpha 1-Antichymotrypsin (ACT) is an an acute phase protein synthesized in response to pro-inflammatory cytokines early in the inflammatory response.

ACT is a member of the serine proteinase inhibitor (serpin) family that inhibits neutrophilic proteinases – chymotrypsin, cathepsin G, chymases from mast cells, and elastase – protecting tissue from damage by these proteolytic enzymes. ACT is a glycoprotein found in alpha(1)-globulin region in human serum. Alpha 1-antichymotrypsin contains a reactive centre loop that interacts with cognate proteinases, resulting in loop cleavage and a major conformational change.

As an acute phase protein, ACT is active in the control of immune and inflammatory responses, and acts as a tumor marker. ACT inhibits CTL-mediated lysis (CML).

ACT has been identified as a major constituent of the neurofibrillary plaques associated with Alzheimers disease, where it probably enhances the rate of amyloid-fibril formation. Genetic data also suggests that alpha 1-antichymotrypsin is important in the pathogenesis of Alzheimer's disease.[s]

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alpha 1-antitrypsin

Alpha 1-antitrypsin or α1-antitrypsin (A1AT) or alpha-1 proteinase inhibitor (α1-PI) is an an acute phase protein synthesized in response to pro-inflammatory cytokines early in the inflammatory response.

A1AT is a 52 kDa prototypical serine protease inhibitor (serpin) that protects against enzymes released by inflammatory cells, particularly elastase, which is released from neutrophilic granules. A1AT forms covalent bonds with both elastase and trypsin, irreversibly inactivating these proteolytic enzymes.

Alpha 1-antitrypsin deficiency is a hereditary disorder in which inability to inactivate elastase and trypsin allows inflammatory tissue breakdown, causing pulmonary emphysema and hepatic cirrhosis in severe cases.

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. . . since 11/21/06