| Description | suitable as substrate for lipase | Inquire | Protein Purity≥85% by SDS PAGEExtinction CoeffA280 nm = 0.631 at 1.0 mg/ml for pure C1qMolecular Weight400,000 Da (18 chains)General DescriptionRat C1q is purified from pooled normal rat serum. C1q is part of the C1 complex, which is the first complement component in the classical pathway of Protein Purity≥85% by SDS PAGEExtinction CoeffA280 nm = 0.631 at 1.0 mg/ml for pure C1qMolecular Weight400,000 Da (18 chains)General DescriptionRat C1q is purified from pooled normal rat serum. C1q is part of the C1 complex, which is the first complement component in the classical pathway of complement. The C1 complex is a non-covalent assembly of three different proteins (C1q, C1r, and C1s) bound together in a calcium-dependent complex. C1q has six extended arms with domains at the end of each arm that bind to the Fc domains of immunoglobulins such as IgG or IgM. When antibodies bind toantigens, forming immune complexes, they cluster allowing two or more of the six C1q arms to bind to the Fc domains of antibodies. Rat IgG2 is very efficient when compared to IgG1 in activating complement (Medgyesi, G.A et., al., 1981). This is in contrast to the human system in which IgG1 activates complement but not IgG2 (Redpath, S. et. al., 1998). The binding of multiple arms of C1q to immune complexes causes the two C1r proteins in the complex (protease zymogens) to auto-activate. The activated C1r proteases cleave and activate the two C1s protease zymogens in the complex. The activated C1s cleaves complement component C4 releasing C4a and initiating covalent attachment of C4b to the activating surface. Activated C1s also cleaves C2 and the larger fragment of C2 binds to the surface-attached C4b forming C4b,C2a, the C3/C5 convertase of the classical pathway.Rat IgG1 cannot activate complement whereas rat IgG2 does.Physical Characteristics & StructureThe apparent molecular weight of rat C1q as determined by gel filtration has been reported to be 400,000 by Veerhuis, R. et al., (1985) and is calculated to be 420,000 based on its amino acid sequence. Rat C1q is a high molecular weight complex of 18 polypeptide chains. Each of the six arms of rat C1q contains three chains, an A chain (~30,000 daltons), a B chain (~28,000 daltons) and a C chain (~26,000 daltons) as determined by SDS/polyacrylamide gel electrophoresis (Wing, M.G. et al., (1993)).FunctionThe biological functions of C1q are described above in the General Description and Physical Characteristics sections.ApplicationsRat C1q can be used to coat ELISA plates to capture and quantitate immune complexes in samples from rat models used for studying immune complex related diseases and conditions.GeneticsNCBI Gene ID numbers for rat C1q are: C1q A chain (298566), C1q B chain (29687), and C1q C chain (362634). The genes for C1q chains A, B and C are all located on chromosome 5. The UniprotKB primary accession numbers for rat C1q are: C1q A chain (P31720), C1q B chain (P31721), and C1q C chain (P31722).Precautions/Toxicity/HazardsThis protein is purified from animal plasma/serum and therefore precautions appropriate for handling any animal blood-derived product must be used.ReferencesMedgyesi, G.A et., Miklos, K., Kulics, J., Fust, G., and Gergely, J. Bazin, H. (1981). Classes and subclasses of rat antibodies: reaction with the antigen and interaction of the complex with the complement system. Immunology 43, 171-176.Redpath, S., Michaelsen, T., Sandlie, I. and Clark, M. R. (1998). Activation of complement by human IgG1 and human IgG3 antibodies against the human leucocyte antigen CD52. Immunology 93, 595–600.Veerhuis, R., Van Es, L.A. and Daha, M.R. (1985). In vivo degradation of rat C1q induced by intravenous injection of soluble IgG aggregates. Immunology 54, 801-810.Wing, M.G., Seilly, D. J., Bridgman, D.J. and Harrison, R.A. (1993). Rapid isolation and biochemical characterization of rat C1 and C1q. Molecular Immunology 30, 433-440... Read More | Purity>97% by SDS-PAGE and HPLC analyses.FunctionMay be involved in macrophage-mediated cellular proliferation. It is mitogenic for fibroblasts and smooth muscle but not endothelial cells. It is able to bind EGF receptors with higher affinity than EGF itself and is a far more potent mitogen for Purity>97% by SDS-PAGE and HPLC analyses.FunctionMay be involved in macrophage-mediated cellular proliferation. It is mitogenic for fibroblasts and smooth muscle but not endothelial cells. It is able to bind EGF receptors with higher affinity than EGF itself and is a far more potent mitogen for smooth muscle cells than EGF. Also acts as a diphtheria toxin receptor.Background:Human HB-EGF (Heparin-Binding EGF-like growth factor) is a 12-16 kDa member of the EGF family of peptide growth factors (1-3). Also known as the DTR (diphtheria toxin receptor), it is further classified as a group 2 ErbB ligand based on its ability to activate both the EGF/ErbB1 and ErbB4 receptors (4, 5). HB-EGF is synthesized as a 208 amino acid (aa) type I transmembrane preproprecursor (1, 6). It contains a 19 aa signal sequence, a 43 aa prosegment, an 86 aa mature region (aa 63-148), an 11 aa juxtamembrane cleavage peptide, a 24 aa transmembrane segment, and a 25 aa cytoplasmic tail (aa 184-208). As an integral membrane protein, HB-EGF is expressed as a 19-27 kDa protein in mammalian cells (7-9). The variability in molecular weight (MW) is attributed to heterogeneity in glycosylation and/or the utilization of multiple proteolytic cleavage sites during maturation. Mature HB-EGF is a soluble peptide that arises from proteolytic processing of the transmembrane form. It possesses an EGF-like domain between aa 104-144, and a heparin-binding motif between aa 93‑113. Although the aa range for "mature" HB-EGF is typically stated to be Asp63-Leu148, potential N-terminal start (cleavage) sites also exist at Gly32, Arg73, Val74, Ser77 and Ala82 (8, 10-12). Thus, differential processing (in part) likely accounts for the 16-23 kDa range in MW noted for mammalian-derived mature HB-EGF. Proteases suggested to contribute to HB-EGF processing include TACE, MMP-3 and -7, ADAM-17 and ADAM-12 (11, 13-16). When expressed recombinantly in E.coli, HB-EGF (aa 73-148) runs at 14 kDa in SDS-PAGE; when expressed in Baculovirus, HB-EGF (aa 63-148, 77-148 and 32-148) runs at 18 kDa, 15 kDa, and 19 kDa respectively (8, 12, 17). Over aa 63-148, human HB-EGF- shares 76% and 73% aa sequence identity with rat and mouse HB-EGF, respectively (1, 18). Cells known to express HB-EGF include bronchial epithelium (19), visceral and vascular smooth muscle (20, 21), CD4+ T cells (22), cardiac muscle (23), glomerular podocytes (24), keratinocytes (13) and IL-10-secreting regulatory macrophages (25). As noted earlier, HB-EGF is known to bind to both 170 kDa EGFR and 180 kDa ErbB4, and through heterodimerization, ErbB2 (13, 26). Activity associated with ErbB4 binding appears to be limited to non-mitogenic actions, while EGFR binding induces both mitogenic and non-mitogenic activity... Read More | Purity>97% by SDS-PAGE and HPLC analyses.Additional sequence informationFunction N-terminal glycine. Full-length mature chain lacking the signal peptideFunctionHas chemotactic activity for neutrophils. May play a role in inflammation and exerts its effects on endothelial cells in an autocrine Purity>97% by SDS-PAGE and HPLC analyses.Additional sequence informationFunction N-terminal glycine. Full-length mature chain lacking the signal peptideFunctionHas chemotactic activity for neutrophils. May play a role in inflammation and exerts its effects on endothelial cells in an autocrine fashion. In vitro, the processed forms GRO-alpha(4-73), GRO-alpha(5-73) and GRO-alpha(6-73) show a 30-fold higher chemotactic activity.Post-translationalN-terminal processed forms GRO-alpha(4-73), GRO-alpha(5-73) and GRO-alpha(6-73) are produced by proteolytic cleavage after secretion from peripheral blood monocytes... Read More |