Alpha 1-antichymotrypsin

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PBB Protein SERPINA3 image.jpg
Available structures
PDB Ortholog search: PDBe RCSB
Aliases SERPINA3, AACT, ACT, GIG24, GIG25, serpin family A member 3
External IDs MGI: 98377 HomoloGene: 111129 GeneCards: 12
RNA expression pattern
PBB GE SERPINA3 202376 at tn.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 14: 94.59 – 94.62 Mb Chr 12: 104.34 – 104.35 Mb
PubMed search [1] [2]
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Alpha 1-antichymotrypsin (α1AC)[3] is an alpha globulin glycoprotein that is a member of the serpin superfamily. In humans, it is encoded by the SERPINA3 gene.


Alpha 1-antichymotrypsin inhibits the activity of certain enzymes called proteases, such as cathepsin G that is found in neutrophils, and chymases found in mast cells, by cleaving them into a different shape or conformation. This activity protects some tissues, such as the lower respiratory tract, from damage caused by proteolytic enzymes.[4]

This protein is produced in the liver, and is an acute phase protein that is induced during inflammation.

Clinical significance[edit]

Deficiency of this protein has been associated with liver disease. Mutations have been identified in patients with Parkinson disease and chronic obstructive pulmonary disease.[5]

Alpha 1-antichymotrypsin is also associated with the pathogenesis of Alzheimer's disease as it enhances the formation of amyloid-fibrils in this disease.[4]


Alpha 1-antichymotrypsin has been shown to interact with DNAJC1.[6]


  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ Logan, Carolynn M.; Rice, M. Katherine (1987). Logan's Medical and Scientific Abbreviations. Philadelphia: J. B. Lippincott Company. p. 3. ISBN 0-397-54589-4. 
  4. ^ a b Kalsheker N (1996). "Alpha 1-antichymotrypsin". Int. J. Biochem. Cell Biol. 28 (9): 961–4. doi:10.1016/1357-2725(96)00032-5. PMID 8930118. 
  5. ^ "Entrez Gene: SERPINA3 serpin peptidase inhibitor, clade A (alpha-1 antiproteinase, antitrypsin), member 3". 
  6. ^ Kroczynska B, Evangelista CM, Samant SS, Elguindi EC, Blond SY (March 2004). "The SANT2 domain of the murine tumor cell DnaJ-like protein 1 human homologue interacts with alpha1-antichymotrypsin and kinetically interferes with its serpin inhibitory activity". J. Biol. Chem. 279 (12): 11432–43. doi:10.1074/jbc.M310903200. PMC 1553221free to read. PMID 14668352. 

Further reading[edit]

External links[edit]