alpha 1-antichymotrypsin alpha 1-antichymotrypsin alpha 1-antichymotrypsin (symbol α1ac, a1ac, or a1act) is an alpha globulin glycoprotein that is a member of the serpin superfamily. in humans, it is encoded by the serpina3 gene. serpina3available structurespdbortholog search: pdbe rcsb list of pdb id codes1as4, 1qmn, 2ach, 3caa, 3dlw, 4caaidentifiersaliasesserpina3, aact, act, gig24, gig25, serpin family a member 3external idsomim: 107280 mgi: 98377 homologene: 111129 genecards: serpina3 gene location (human)chr.chromosome 14 (human)band14q32.13start94,612,384 bpend94,624,055 bpgene location (mouse)chr.chromosome 12 (mouse)band12 e|12 53.99 cmstart104,304,745 bpend104,312,403 bprna expression patternbgeehumanmouse (ortholog)top expressed inright lobe of liverbody of pancreasislet of langerhansgastric mucosaleft coronary arteryright coronary arterygallbladderleft uterine tuberight lungminor salivary glandtop expressed inleft lobe of liversexually immature organismpharynxparotid glandspinal gangliaadrenal glandwhite adipose tissueduodenumright lung lobeesophagusmore reference expression databiogpsmore reference expression datagene ontologymolecular function peptidase inhibitor activity dna binding protein binding serine-type endopeptidase inhibitor activity cellular component blood microparticle extracellular exosome intracellular anatomical structure nucleus platelet alpha granule lumen extracellular region extracellular space secretory granule lumen azurophil granule lumen collagen-containing extracellular matrix biological process regulation of lipid metabolic process negative regulation of peptidase activity inflammatory response maintenance of gastrointestinal epithelium acute-phase response platelet degranulation negative regulation of endopeptidase activity neutrophil degranulation sources:amigo / quickgoorthologsspecieshumanmouseentrez1220714ensemblensg00000196136ensmusg00000058207uniprotp01011p07759refseq (mrna)nm_001085nm_011458refseq (protein)np_001076np_035588location (ucsc)chr 14: 94.61 – 94.62 mbchr 12: 104.3 – 104.31 mbpubmed searchwikidataview/edit humanview/edit mouse function 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. this protein is produced in the liver, and is an acute phase protein that is induced during inflammation. clinical significance deficiency of this protein has been associated with liver disease. mutations have been identified in patients with parkinson disease and chronic obstructive pulmonary disease. alpha 1-antichymotrypsin is also associated with the pathogenesis of alzheimer's disease as it enhances the formation of amyloid-fibrils in this disease. interactions alpha 1-antichymotrypsin has been shown to interact with dnajc1.