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C1740 Sigma-Aldrich

Complement component C1q from human serum

≥95% (SDS-PAGE)



Related Categories Biochemicals and Reagents, Complement, Plasma & Blood Proteins, Plasma, Blood, and Related Proteins and Reagents, Proteins and Derivatives More...
Quality Level   200
biological source   human
assay   ≥95% (SDS-PAGE)
form   liquid
application(s)   activity assay: suitable
shipped in   dry ice
storage temp.   −70°C
Gene Information   human ... C1QA(712), C1QB(713), C1QC(714)


General description

C1q, together with C1r and C1s, in the ratio of 1:2:2, form the C1 complex which is the first component of the classical complement pathway. C1q is composed of 18 polypeptide chains (six A, six B, six C) (MW 460 kDa). All contain an 81-aa collagen-like region composed of (Gly-Xaa-Yaa) repeating sequences close to the N-terminus. Three chains (A1B1C1) form a triple helix with the C-terminus forming the globular heads which may be structurally and functionally distinct domains.


Complement component C1q is an important regulator factor for platelet activation. This has been a topic for research, as platelet-leukocyte aggregates play an important role in inflammatory conditions such as coronary heart disease. In particular, C1q has been shown to inhibit collagen induced aggregation and enhance production of reactive oxygen species (ROS).

Biochem/physiol Actions

C1q deficiency, either because of rare homozygous genetic defect, or transcriptional/translational defects, is almost certainly a cause of systemic lupus erythematosus (SLE). The three C1q subunits are expressed through a novel mechanism of transcriptional synchronization.

Physical form

Supplied as a solution in 10 mM HEPES, 300 mM NaCl, pH 7.2

Safety & Documentation

Safety Information

NONH for all modes of transport
WGK Germany 


Certificate of Analysis (COA)

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Certificate of Origin (COO)

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Protocols & Articles


Plasma Derived Proteins and Enzymes

Despite their complexity, blood and plasma are abundant biological resources for the discovery of drug targets and biomarkers for human disease. It is estimated that plasma may contain as many as 40,...
BioFiles 2006, 1.5, 2.
Keywords: Applications, Gas chromatography, Type

Peer-Reviewed Papers


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