Complement C1q, Human

Native, human C1q complement component. Glycoprotein composed of 18 polypeptide chains consisting of three nonidentical subunits, A, B, and C, of M.W. 29 kDa, 26 kDa, and 19 kDa, respectively. Present in normal human serum at 70 µg/ml. Found in circulating blood plasma complexed with two C1r and two C1s molecules to form the first component of complement (C1). Activation of complement via classical pathway is triggered by binding of C1q to immune complexes containing IgG or IgM or to a variety of other activating substances, including C-reactive protein, retroviruses, and mitochondria. Subsequent to C1q binding, C1r and C1s are converted to proteolytic enzymes that are responsible for continuation of activation via the classical pathway.

≥150,000 C1qH50 units/mg and ≥70% C1q activity in normal human serum on a mg/mg basis

Please refer to vial label for lot-specific concentration.

In 300 mM NaCl, 10 mM HEPES, 40% glycerol, pH 7.2.

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

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

Loos, M., et al. 1980. J. Immunol. 124, 59.
Kolb, W.P., et al. 1979. J. Immunol. 122, 2103.

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Toxicity: Standard Handling (A)