| Description | Lens culinaris lectin or agglutinin (LCA) is isolated from Lens culinaris (lentil) seeds and purified by affinity chromatography. The lectin has two subunits and a molecular weight of 46 kDa and it forms a complex together with sucrose. Lectins are, due to their specific binding to carbohydrate Lens culinaris lectin or agglutinin (LCA) is isolated from Lens culinaris (lentil) seeds and purified by affinity chromatography. The lectin has two subunits and a molecular weight of 46 kDa and it forms a complex together with sucrose. Lectins are, due to their specific binding to carbohydrate struc- tures on the cell surface or elsewhere useful in haematology, immunology or as specific markers for membrane glycoprotein structures. LCA’s carbohydrate specificity is D-mannose and D-glucose and the two isomers LCA-A and LCA-B agglutinates human red blood cells, although this reaction is not blood group specific. LCA is also a useful component in affinity chroma- tography columns for the separation of glycoconjugates. Lens culinaris lectin is supplied as a white lyophilized powder from 1 mM CaCl2, 1 mM MnCI2 and 1 mM MgCI2. No preservatives are added. In isoelectric focusing, the lectin generates two major bands at pI 8.15, 8.45 and one minor band at pI 8.65. The activity of the lectin is determined by haemagglutination with human blood. Lens culinaris lectin agglutinates a 2% suspension of human erythrocytes at a lectin concentration of ≤8 µg/ml in 0.9% saline solution (NaCl) after 2 h at 25°C. Adding 60 mM methylmannoside yields an inhibition with a lectin titer that is at least 16-fold weaker than the control.Addition of Mn2+ and Ca2+ to the reconstitution buffer will enhance hemagglutination activity. ● Ultrapure quality ● Sugar specificity: α-D-mannose and α-D-glucose ● Haemagglutinating activity ● Lyophilized powderHaemagglutination studies;Cell agglutination studies;Component in affinity columns;Separation of glycoconjugates... Read More | 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≥95% SDS-PAGE.Endotoxin level<0.1 EU/µgFunctionMediates NK cell adhesion and triggers NK cell effector functions. Binds two different NK cell receptors: CD96 and CD226. These interactions accumulates at the cell-cell contact site, leading to the formation of a mature Purity≥95% SDS-PAGE.Endotoxin level<0.1 EU/µgFunctionMediates NK cell adhesion and triggers NK cell effector functions. Binds two different NK cell receptors: CD96 and CD226. These interactions accumulates at the cell-cell contact site, leading to the formation of a mature immunological synapse between NK cell and target cell. This may trigger adhesion and secretion of lytic granules and IFN-gamma and activate cytoxicity of activated NK cells. May also promote NK cell-target cell modular exchange, and PVR transfer to the NK cell. This transfer is more important in some tumor cells expressing a lot of PVR, and may trigger fratricide NK cell activation, providing tumors with a mechanism of immunoevasion. Plays a role in mediating tumor cell invasion and migration. Serves as a receptor for poliovirus attachment to target cells. May play a role in axonal transport of poliovirus, by targeting virion-PVR-containing endocytic vesicles to the microtubular network through interaction with DYNLT1. This interaction would drive the virus-containing vesicle to the axonal retrograde transport... Read More | Purity＞97% by SDS-PAGE and HPLC analyses.FunctionPigment epithelium-derived factor (PEDF) is encoded by the SERPINF1 gene in humans and found in verebrates. It is a secreted phosphoglycoprotein that belongs to the clade F subfamily, serpin superfamily of proteinase inhibitors. The PEDF is a Purity＞97% by SDS-PAGE and HPLC analyses.FunctionPigment epithelium-derived factor (PEDF) is encoded by the SERPINF1 gene in humans and found in verebrates. It is a secreted phosphoglycoprotein that belongs to the clade F subfamily, serpin superfamily of proteinase inhibitors. The PEDF is a noninhibitory serpin with neurotrophic, anti-angiogenic, and anti-tumorigenic properties. It is synthesized as a 418 a.a. about 50kDa precursor that contains a 19 a.a. signal sequence and a 399 a.a. mature region that shows a pyroglutamate at Gln20. Like other serpins, it contains three β-sheets, 810 α-helices, and a C-terminal RCL (reactive center loop). Unlike other serpins with Ser protease inhibiting activity. PEDF has functions of inducing extensive neuronal differentiation in retinoblastoma cells, inhibiting of angiogenesis. As it does not undergo the S (stressed) to R (relaxed) conformational transition characteristic of active serpins, it exhibits no serine protease inhibitory activity. PEDF is researched as a therapeutic candidate for treatment of such conditions as choroidal neovascularization, heart disease, and cancer... Read More |