a2-Macroglobulin (HRP)

a2Macroglobulin (a2M) is a large proteinase inhibitor molecule of 718kD, consisting of 4 identical subunits of 185kD each. Produced in hepatocytes and macrophages, plasma concentrations of a2M are typically 2uM in adults, and as high as 6uM in childhood. a2M has the ability to inhibit most enzymes from the serine, metallo, cysteine and aspartate subclasses. It is not a member of the SERPIN family of inhibitors. It belongs to a class of 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-_-glutamyl thiolester bonds, which in the case of a2M are susceptible to cleavage by enzymes or by nucleophilic compounds such as methylamine or ammonium ions. Although the precise nature of the interactions is as yet unknown, it is generally thought that cleavage of a bait region within the a2M molecule by an enzyme leads to 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 induced also exposes receptor-binding regions within the molecule, which may be important in the clearance of a2M-enzyme complexes from the circulation. It is thought that the main role of a2M in vivo is that of a

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SPECIFICATIONS

Catalog Number

M1150-20B

Size

100ug

Applications

ELISA

Hosts

Goat

Reactivities

Hum, Mouse, Rat, Can, Prc, Rabbit

Form

Supplied as a liquid in a buffered stabilizer solution, 50% glycerol. No preservatives are added. Labeled with HRP. \nRz ratio (Reinheitszahl, A403/A280): 0.29 (determined spectrophotometrically).

P Type

Pab

Purity

Purified by affinity chromatography.

Isotype

IgG

References

1. Salvesen, G., Pizzo, S.V., Hemostasis and Thrombosis 3rd Edition, eds. R.W. Colman, J. Hirsh, V.J. Marder, E.W. Salzman, pp. 241-258, J.B. Lippincott Co., Philadelphia PA, USA, 1994. 2. Barrett J., Methods in Enzymology, 80: 737-754, 1981. 3. Larsson, L.J., et al., Biochemistry 28: 7636-7643, 1989. 4. Schmidt, B., et al., Thromb Haemostas 62: 1074-1077, 1989. 5. Hoogendoorn, H., et al., Blood 78: 2283-2290, 1991.

Additional Info

Recognizes human alpha2 Macroglobulin. Species Crossreactivity: mouse, porcine, canine, rat and rabbit.