| Description | Human IgG Antibody; Isotype Control Antibody, could be used for Flow Cytometry | C1q separated from C1r and C1s and from other stabilizing proteins tends to aggregate easily. Because it was isolated and studied in numerous research laboratories, many buffers have been used to stabilize concentrated C1q and prevent aggregation. About half of the scientists prefer high salt and C1q separated from C1r and C1s and from other stabilizing proteins tends to aggregate easily. Because it was isolated and studied in numerous research laboratories, many buffers have been used to stabilize concentrated C1q and prevent aggregation. About half of the scientists prefer high salt and the other prefer 40% glycerol in the storage buffer.C1q is purified from pooled normal human plasma. C1q is part of the C1 complex and this complex is the first complement component in the cascade referred to as the classical pathway of complement. C1 is actually 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. When antibodies bind to antigens forming immune complexes they cluster allowing two or more of its six arms of C1q to bind to the Fc domains of antibodies such as IgG or IgM. The binding of multiple arms to immune complexes causes the two C1r proteins in the complex (protease zymogens) to auto-activate producing two C1r proteases that cleave and activate the two C1s protease zymogens in the complex. 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 which is the C3/C5 convertase of the classical pathway.Extinction Coeff.A₂₈₀ nm = 0.68 at 1.0 mg/ml for pure C1q Molecular weight:410,000 Da (18 chains)Preservative:None, 0.22 µm filtered.Source:Normal human serum (shown by certified tests to be negative for HBsAg, HTLV-I/II, STS, and for antibodies to HCV, HIV-1 and HIV-II).Physical Characteristics & StructureC1q is a high molecular weight complex of 18 polypeptide chains. Each of the six arms of C1q contains three chains, an A chain (26,000 daltons), a B chain (25,000 daltons) and a C chain (24,000 daltons). The three chains are coiled into a collagen-like triple helix over approximately half their length. Half of this collagen region forms a central core where all 18 chains come together. The chains are joined in this core by disulfides in the pattern A-B and C-C. There is a bend in the center of the collagen region allowing the arms to extend away from each other. Globular heads at the far ends of the collagen arms possess binding sites for Fc domains of immunoglobulins. C1 complex is composed of one C1q molecule (410,000 daltons), two C1r molecules (92,000 daltons) and two C1s molecules (86,000 daltons). The complex is stable in the presence of calcium, but easily dissociates if calcium is removed. When C1 is activated the C1r and C1s subunits are each cleaved into two chain molecules due to proteolytic activation. Thus, the SDS gel pattern of C1 is very complex. Function The biological functions of C1q are described above in the General Description and Physical Characteristics sections. C1q functional activity may be assayed using C1q-depleted serum and EA cells. These assays are extremely sensitive to C1q typically yielding 50% lysis with less than 2 ng C1q in assays measuring the lysis of EA cells. AssaysThe unit of classical pathway activity is the CH50. A similar unit, the C1qH50, is used to quantitate the activity of C1q. A C1qH50 unit is the amount of functional C1q needed to lyse 50% of 3×10^7 EA cells (antibody-sensitized sheep erythrocytes) when that amount of C1q is incubated with 5-20 µL of C1q-Dpl in GVB++ in a total volume of 500 µL for 30 min at 37℃. This amount of C1q indicates the sensitivity of the assay for C1q which is typically about 1 ng C1q with 10 µL C1q-Dpl. See the Certificate of Analysis for lot specific values.ApplicationsC1q is used to coat ELISA plates to capture and quantitate immune complexes in clinical samples. A number of commercial companies sell diagnostic kits for immune complex detection and quantitation. These kits are based on the ability of C1q to bind well to immune complexes, but to not bind significantly to monomeric immunoglobulins. GeneticsThe EMBL/Genbank cDNA accession numbers are: C1q A chain (P02745), C1q B chain (P02746), and C1q C chain (P02747). The genes for C1q chains A, B and C are all located on chromosome 1p in the order A-C-B. DeficienciesDeficiencies of each of the three components of C1 have been found. Patients lacking C1q generally have immune-complex-mediated renal disease and skin lesions. Like all patients lacking early classical pathway components C1q deficient individuals are prone to systemic lupus erythrematosis (SLE) and recurrent pyogenic infections. They lack classical pathway function and may or may not exhibit C1q antigen in blood.DiseasesSee section titled Deficiencies above. Precautions/Toxicity/HazardsThis protein is purified from human serum and therefore precautions appropriate for handling any blood-derived product must be used even though the source was shown by certified tests to be negative for HBsAg, HTLV-I/II, STS, and for antibodies to HCV, HIV-1 and HIV-II... Read More | Inquire | Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description: DCX (doublecortin, N-GST chimera)contains 2 doublecortin domains and belongs to the doublecortin family. It is highly expressed in neuronal cells of fetal brain, but not expressed in other fetal tissues. In the Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description: DCX (doublecortin, N-GST chimera)contains 2 doublecortin domains and belongs to the doublecortin family. It is highly expressed in neuronal cells of fetal brain, but not expressed in other fetal tissues. In the adult, it is highly expressed in the brain frontal lobe, but very low expression in other regions of brain, and not detected in heart, placenta, lung, liver, skeletal muscles, kidney and pancreas. DCX is a microtubule-associated protein required for initial steps of neuronal dispersion and cortex lamination during cerebral cortex development. It may act by competing with the putative neuronal protein kinase DCAMKL1 in binding to a target protein. DCX may in that way participate in a signaling pathway that is crucial for neuronal interaction before and during migration, possibly as part of a calcium ion-dependent signal transduction pathway. It may be part with LIS-1 of a overlapping, but distinct, signaling pathways that promote neuronal migration. Defects in DCX are the cause of lissencephaly X-linked type 1 and subcortical band heterotopia X-linked... Read More | Fibroblast growth factor-21 (FGF-21) belongs to the large FGF family and it is specifically induced by HMGCS2 activity. In mice, brown adipose tissue becomes a source of systemic FGF21 after cold exposure. FGF-21 stimulates glucose uptake in differentiated adipocytes via the induction of glucose Fibroblast growth factor-21 (FGF-21) belongs to the large FGF family and it is specifically induced by HMGCS2 activity. In mice, brown adipose tissue becomes a source of systemic FGF21 after cold exposure. FGF-21 stimulates glucose uptake in differentiated adipocytes via the induction of glucose transporter SLC2A1/GLUT1 expression and the activity depends on the presence of KLB. FGF-21, in the presence of β-Klotho as a protein cofactor, signals through the FGFR 1c and 4 receptors. Murine FGF-21 shows limited binding to heparin. In addition, Murine FGF-21 respectively shows 81% and 92% a.a. identity to human and rat FGF-21, and it show activity on human and rat cells. Recombinant Murine FGF21 is a 19.9kDa globular protein containing 182 amino acid residues.Purity>96%(SDS-PAGE, HPLC)Additional sequence informationA single non-glycosylated polypeptide chain containing 182 amino acids. This product is for the mature full length protein. The signal peptide is not included.FunctionStimulates glucose uptake in differentiated adipocytes via the induction of glucose transporter SLC2A1/GLUT1 expression (but not SLC2A4/GLUT4 expression). Activity requires the presence of KLB... Read More |