Alpha2 Macroglobulin (a-2M) is a large proteinase inhibitor molecule of 718kD, consisting of 4 identical subunits of 185,000 each. It is produced in hepatocytes and macrophages, and generally found in plasma concentrations of 2uM in adults, and up to 6uM in children. a-2M inhibits most enzymes from the serine, metallo, cysteine and aspartate subclasses. It is classed with proteins that include pregnancy zone protein (PZP) and the complement proteins C3, C4 and C5. These proteins contain regions of conserved sequence as well as one or more internal b-cysteinyl-g-glutamyl thiolester bonds. In a-2M, these regions are susceptible to cleavage by enzymes or by nucleophilic compounds such as methylamine or ammonium ions. It is thought that enzymatic cleavage of a bait region within the a-2M molecule causes a conformational change, which then traps and/or covalently binds the enzyme (1,2). The active site of the trapped enzyme is usually still intact and able to cleave small substrates, but is inaccessible to larger natural substrates. The conformational change also exposes receptor-binding regions within the molecule, which may be important in the clearance of a-2M enzyme complexes from the circulation. It is thought that the main role of a-2M in vivo is ''backup inhibitor and scavenger of proteinases in blood and in tissues (3,4). It has also been reported to participate in other physiological processes, including regulation of immune function (1,2). Application: Suitable for use in ELISA and Immunoelectrophoresis. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Also Available: Cat M1150-20: Affinity purified Macroglobulin, alpha2 Cat M1150-20B: Macroglobulin, alpha2 (HRP)
Purity:
Purified by caprylic acid and ammonium sulfate precipitations, and solid -phase adsorption to remove unwanted crossreactivity.
Form:
Supplied as a liquid in 0.01M HEPES, pH 7.4, 0.1M sodium chloride, 50% glycerol.
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