Alpha-2-macroglobulin is a protease inhibitor and cytokine transporter. It inhibits many proteases, including trypsin, thrombin and collagenase. A2M is implicated in Alzheimer disease (AD) due to its ability to mediate the clearance and degradation of A-beta, the major component of beta-amyloid deposits. [provided by RefSeq, Jul 2008].
Function:
Is able to inhibit all four classes of proteinases by a unique 'trapping' mechanism. This protein has a peptide stretch, called the 'bait region' which contains specific cleavage sites for different proteinases. When a proteinase cleaves the bait region, a conformational change is induced in the protein which traps the proteinase. The entrapped enzyme remains active against low molecular weight substrates (activity against high molecular weight substrates is greatly reduced). Following cleavage in the bait region a thioester bond is hydrolyzed and mediates the covalent binding of the protein to the proteinase.
Subunit:
Homotetramer; disulfide-linked.
Subcellular Location:
Secreted
Tissue Specificity:
Secreted in plasma
Similarity:
Belongs to the protease inhibitor I39 (alpha-2-macroglobulin) family.
SWISS:
P01023
Gene ID:
2
Database links:
Entrez Gene: 2 Human
Entrez Gene: 232345 Mouse
Entrez Gene: 24153 Rat
Omim: 103950 Human
SwissProt: P01023 Human
SwissProt: Q61838 Mouse
SwissProt: P06238 Rat
Unigene: 212838 Human
Unigene: 30151 Mouse
Unigene: 225884 Rat
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