Complement C3b, Human

Complement C3b, Human, is a native C3b complement component. It is a glycoprotein composed of the modified C3-α chain (αʹ) (M.W. 105,000) and the intact C3-β chain (M.W. 75,000).

storage conditions

= -70C

Quality Level


≥90% (SDS-PAGE)





storage condition

OK to freeze
avoid repeated freeze/thaw cycles


IgG, IgA, IgM, C5, Factor H, or Factor I, trace

shipped in

wet ice

General description

Native, human C3b complement component. Cleavage of the C3-α chain at peptide bond 77 by either of the complement C3 convertase enzymes results in production of C3a (M.W. 9083) and C3b (M.W. 180,000) fragments. The C3b fragment is a glycoprotein composed of the modified C3-α chain (α′) (M.W. 105,000) and the intact C3-β chain (M.W. 75,000). Nascent C3b has the transient ability to form a covalent ester bond with a variety of target surfaces. Once bound to target surfaces C3b becomes an essential subunit of both the classical and alternative pathway C5 cleaving enzymes. In addition, surface-bound C3b has opsonic and immune adherence activities which are mediated via binding to CR1 (CD35) complement receptors.


250 μg in Plastic ampoule


Toxicity: Standard Handling (A)

Physical form

In PBS, pH 7.2, filtered through a 0.22 µm filter.

Preparation Note

Prepared from serum that has been shown by certified tests to be negative for HBsAg and for antibodies to HIV and HCV.


Following initial thaw, aliquot and freeze (-70°C).

Other Notes

Wong, W.W. and Fearon, D.T. 1987. Methods Enzymol.150, 579.
Arnout, M.A., et al. 1981. J. Immunol.127, 1348.

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis
Certificate of Origin

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