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alpha-1-antichymotrypsin; ACT; cell growth-inhibiting gene 24/25 protein; Serpin A3 (SERPINA3, AACT, GIG24, GIG25)
Function:
- physiological function is unclear
- inhibits neutrophil cathepsin G & mast cell chymase, both of which can convert angiotensin-1 to the active angiotensin-2
- interacts with DNAJC1
Structure:
- the reactive center loop (RCL) extends out from the body of the protein & directs binding to the target protease
- the protease cleaves the serpin at the reactive site within the RCL, establishing a covalent linkage between the carboxyl group of the serpin reactive site & the Ser hydroxyl of the protease
- resulting inactive serpin-protease complex is highly stable
- belongs to the serpin family
Compartment:
- secreted
- occurs normally in bronchial secretions
Expression:
- plasma
- synthesized in the liver
- concentration increases in the acute phase of inflammation or infection. found in the amyloid
Pathology:
- found in senile plaques of patients with Alzheimer's disease, thus may be secreted by neurons, glial cells, or the choroid epithelium
Notes:
- alpha-1-antichymotrypsin can bind DNA
- uncertain whether Met-1 or Met-4 is the initiator
Interactions
molecular events
Related
alpha-1 antichymotrypsin Ag in tissue
alpha-1 antichymotrypsin in specimen
General
acute phase protein
glycoprotein
inter alpha globulin
serine protease inhibitor; serpin
Properties
SIZE: entity length = 423 aa
MW = 48 kD
COMPARTMENT: plasma
MOTIF: signal sequence {1-23}
N-glycosylation site {N33}
N-glycosylation site {N93}
N-glycosylation site {N106}
N-glycosylation site {N127}
N-glycosylation site {N186}
DNA-binding motif
SITE: 235-237
N-glycosylation site {N271}
RCL {369-394}
MOTIF: peptide motif {383-384}
INHIBITS: serine protease
SECRETED-BY: hepatocyte
epithelial cell
WITHIN: bronchus
Database Correlations
OMIM 107280
UniProt P01011
Pfam PF00079
Entrez Gene 12
Kegg hsa:12; -.
References
- Entrez Gene :accession 12
- UniProt :accession P01011
- Wikipedia; Note: alpha-1 antichymotrypsin entry
http://en.wikipedia.org/wiki/alpha_1-antichymotrypsin
Component-of
molecular complex