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Alpha-2-macroglobulin
ProteinQ22680187· pop 12· linked from 145 articles

Alpha-2-macroglobulin

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Also known as C3 and PZP-like alpha-2-macroglobulin domain-containing protein 5, A2M, alpha-2-M

α2-Macroglobulin (α2M) or alpha-2-macroglobulin is a large (720 KDa) plasma protein found in the blood. It is mainly produced by the liver, and also locally synthesized by macrophages, fibroblasts, and adrenocortical cells. In humans it is encoded by the A2M gene.

Protein · UniProt

Alpha-2-macroglobulin

Gene
A2M
Organism
Homo sapiens (Human)
Length
1,474 aa
Molecular mass
163,291 Da
Evidence
1: Evidence at protein level

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 prote…

3D-structureBait regionDirect protein sequencingDisulfide bondGlycoproteinIsopeptide bondProtease inhibitorProteomics identification
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Swiss-Prot (reviewed) · via UniProt

~6 min read

Encyclopedic overview

5 sections
Contents
  • Structure
  • Function
  • Disease
  • References
  • External links

α2-Macroglobulin (α2M) or alpha-2-macroglobulin is a large (720 KDa) plasma protein found in the blood. It is mainly produced by the liver, and also locally synthesized by macrophages, fibroblasts, and adrenocortical cells. In humans it is encoded by the A2M gene.

α2-Macroglobulin acts as an antiprotease and is able to inactivate an enormous variety of proteinases. It functions as an inhibitor of fibrinolysis by inhibiting plasmin and kallikrein. It functions as an inhibitor of coagulation by inhibiting thrombin. α2-macroglobulin may act as a carrier protein because it also binds to numerous growth factors and cytokines, such as platelet-derived growth factor, basic fibroblast growth factor, TGF-β, insulin, and IL-1β.

Excerpted from Wikipedia’s “Alpha-2-macroglobulin” article, available under the CC BY-SA 4.0 licence.

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