| Description | Extinction CoeffA280 nm = 1.15 at 1.0 mg/mL for pure C1sMolecular Weight92,000 Da (1 chain)Protein Purity>90 % by SDS PAGEGeneral Description C1r proenzyme is a single chain 92,000 dalton protein that is the native form of C1r enzyme. C1r is a subunit of the C1 complex which is the first Extinction CoeffA280 nm = 1.15 at 1.0 mg/mL for pure C1sMolecular Weight92,000 Da (1 chain)Protein Purity>90 % by SDS PAGEGeneral Description C1r proenzyme is a single chain 92,000 dalton protein that is the native form of C1r enzyme. C1r is a subunit of the C1 complex which is the first complement component in the cascade referred to as the classical pathway of complement. C1r proenzyme is an inactive zymogen until C1 is activated. C1r is activated when C1 binds to and is activated by antibodies bound to antigens (immune complexes) yielding C1r enzyme, the first protease that initiates the cascade. C1 is a non-covalent calciumdependent complex of one C1q, two C1r and two C1s molecules. Each C1q binds through two or more of its six arms to the Fc domains of IgG or IgM. The binding of multiple arms to immune complexes causes the two C1r proteins in the complex (protease zymogens) to activate producing two proteases that cleave and activate the two C1s protease zymogens in the complex (Morikis, D. and Lambris, J.D. (2005)). The activation of C1r results from cleavage of C1r into two fragments of 57,000 and 35,000 daltons. Activation of the bound C1s molecule is the only known function of C1r enzyme. 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. Physical Characteristics & Structure C1r proenzyme is a 92,000 dalton, single chain peptide that exhibits trypsin-like proteolytic specificity for arginyl bonds present in its two natural substrates, C1s and itself. C1r is present in plasma at 34 ug/mL (0.2µM) (Cooper, 1985). C1r proenzyme is an unstable zymogen and it spontaneously activates (Dodds, A.W. and Sim, R.B. editors (1997); Morikis, D. and Lambris, J.D. editors. (2005)) by cleaving a peptide bond in C1r producing a 57,000 dalton heavy chain and a 35,000 dalton light chain. This is the form sold as C1r enzyme. This self-activation occurs rapidly in the C1 complex upon binding to an immune complex and it occurs slowly with pure C1r. Two C1r form a C1r-C1r complex in the presence of calcium which in turn forms a stable complex with two C1s molecules in the presence of calcium. This tetramer can exist in solution, but in the presence of C1q it binds to C1q forming the C1 complex, which is stable in the presence of calcium. C1r self-activation is controlled in part by a weak association with C1esterase inhibitor (C1-INH) when it is in the C1 complex and similar stabilization occurs with purified C1r (Ziccardi, R.J. (1982)). C1r enzyme, however, is irreversibly inactivated by binding to C1-INH. Function The biological functions of C1r proenzyme are described above in the General Description and Physical Characteristics sections. C1r proenzyme can be used in the presence of calcium to form the C1 complex with C1q and C1s proenzyme. The C1r proenzyme will rapidly self-activate to C1r enzyme when the C1q in the C1 complex binds to immune complexes such as EA cells bearing antibodies. EA are sheep erythrocytes with rabbit IgM anti-sheep erythrocytes antibodies bound to their surface(Morgan, B.P. ed. (2000)). The activated C1r enzyme will rapidly activate the two C1s proenzymes to form C1s enzymes and the resulting C1q-C1r2-C1s2 complex is a fully active C1 molecule which will activate C4 and C2 (Dodds, A.W. and Sim, R.B. editors (1997); Morgan, B.P. ed. (2000)). AssaysThe unit of classical pathway activity is the CH50. A similar unit, the C1rH50, can be used to quantitate the activity of C1r proenzyme for which we have developed a hemolytic assay. The C1rH50 assay uses our newly developed C1r-Dpl and measures the lysis of EA (classical pathway) as a function of the concentration of added test sample or standard purified C1r proenzyme. A C1rH50 unit is the amount of functional C1r proenzyme needed to lyse 50% of 3 x 10⁷EA cells (antibodysensitized sheep erythrocytes when that amount of C1r proenzyme is incubated with the recommended volume of C1r-Dpl in GVB⁺⁺ in a total volume of 500 µL for 30 min at 37℃. This amount of C1r proenzyme indicates the sensitivity of the assay for C1r proenzyme which is typically less than 10 ng C1r proenzyme with 10 µL C1r-Dpl. See the Certificate of Analysis for lot specific values.ApplicationsSee sections titled Function and Assays above. Regulation Activated C1r is rapidly inactivated by C1-INH. The spontaneous activation of C1r observed with pure C1 and pure C1r proenzyme is minimized by the presence of C1- INH which rapidly inactivates spontaneously activated C1r enzyme. Stabilization of the proenzyme is also due to existence of a weak complex between C1-INH and C1r proenzyme. This association apparently stabilizes C1 thus preventing spontaneous activation in serum (Ziccardi, R.J. (1982)). Separation of C1-INH from C1 during purification is one of the reasons that isolated C1 and C1r proenzyme are unstable and prone to spontaneous activation. Genetics The EMBL/Genbank cDNA accession number for C1r is M14058. The genes for C1r and C1s are closely linked and located on chromosome 12p13. DeficienciesDeficiencies of each of the three components of C1 have been found (Ross, G.D. (1986)). C1r and C1s deficient patients are prone to systemic lupus erythematosus (SLE) and recurrent pyogenic infections (Rother, K., et al. (1998)). They lack classical pathway function and may or may not exhibit C1r 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 | Inquire | Purity> 95 % by SDS-PAGE and HPLC analyses.FunctionPromotes cell proliferation, chemotaxis, angiogenesis and cell adhesion. Appears to play a role in wound healing by up-regulating, in skin fibroblasts, the expression of a number of genes involved in angiogenesis, inflammation and matrix Purity> 95 % by SDS-PAGE and HPLC analyses.FunctionPromotes cell proliferation, chemotaxis, angiogenesis and cell adhesion. Appears to play a role in wound healing by up-regulating, in skin fibroblasts, the expression of a number of genes involved in angiogenesis, inflammation and matrix remodeling including VEGA-A, VEGA-C, MMP1, MMP3, TIMP1, uPA, PAI-1 and integrins alpha-3 and alpha-5. CYR61-mediated gene regulation is dependent on heparin-binding. Down-regulates the expression of alpha-1 and alpha-2 subunits of collagen type-1. Promotes cell adhesion and adhesive signaling through integrin alpha-6/beta-1, cell migration through integrin alpha-v/beta-5 and cell proliferation through integrin alpha-v/beta-3.Banckground:Cyr61, also known as CCN1, is a 40-45 kDa matricellular glycoprotein that plays an important role in cellular adhesion and migration (1). Cyr61 consists of an IGFBP domain, a VWF type C domain, a TSP type I domain, and a cysteine knot domain (2). Mature human Cyr61 shares 93% amino acid sequence identity with mouse and rat Cyr61. It is widely expressed during development and in adult tissues (2, 3). Cyr61 associates with the extracellular matrix (ECM) and with many cell surface molecules including Integrins alpha V beta 3, alpha V beta 5, alpha M beta 2, and alpha 6 beta 1, Syndecan-4, and heparan sulfate proteoglycans (1, 3). Cyr61 mediates the adhesion and migration of multiple cell types and also promotes vascular endothelial cell tubule formation (4-6). Plasmin cleavage of ECM-bound Cyr61 releases a 28 kDa N-terminal fragment which retains the ability to promote endothelial cell migration (7). Cyr61 exhibits both tumorigenic and tumor suppressor properties. It is up-regulated and promotes tumorigenesis, angiogenesis, and metastasis in breast, renal, gastric, squamous cell, and colorectal carcinomas as well as in glioma (8-12). In contrast, whendown-regulated, it suppresses tumor growth in endometrial, hepatic, and non-small cell lung cancers (8, 13, 14). Cyr61 is also up-regulated in injured skin and bone where it induces the expression of growth factors, cytokines, proteases, and integrins involved in wound repair (15, 16)... Read More | Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description: High-mobility group box 1 protein (HMGB1), also known as HMG-1 or amphoterin previously, is a member of the HMGB family consisting of three members, HMGB1, HMGB2, and HMGB3. HMGB1 is a DNA-binding nuclear protein,Purity:>90%, by SDS-PAGE visualized with Coomassie® Blue Staining.Description: High-mobility group box 1 protein (HMGB1), also known as HMG-1 or amphoterin previously, is a member of the HMGB family consisting of three members, HMGB1, HMGB2, and HMGB3. HMGB1 is a DNA-binding nuclear protein, released actively following cytokine stimulation as well as passively during cell death. It is the prototypic damage-associated molecular pattern (DAMP) molecule and has been implicated in several inflammatory disorders. HMGB1 signals via the receptor for advanced glycation end-product (RAGE) and members of the toll-like receptor (TLR) family. The most prominent HMGB1 protein and mRNA expression arthritis are present in pannus regions, where synovial tissue invades articular cartilage and bone. HMGB1 promotes the activity of proteolytic enzymes, and osteoclasts need HMGB1 for functional maturation. As a non-histone nuclear protein, HMGB1 has a dual function. Inside the cell, HMGB1 binds DNA, regulating transcription, and determining chromosomal architecture. Outside the cell, HMGB1 can serve as an alarmin to activate the innate system and mediate a wide range of physiological and pathological responses. Extracellular HMGB1 represents an optimal " necrotic marker" selected by the innate immune system to recognize tissue damage and initiate reparative responses. However, extracellular HMGB1 also acts as a potent pro-inflammatory cytokine that contributes to the pathogenesis of diverse inflammatory and infectious disorders. HMGB1 has been successfully therapeutically targeted in multiple preclinical models of infectious and sterile diseases including arthritis. As shown in studies on patients as well as animal models, HMGB1 can play an important role in the pathogenesis of the rheumatic disease, including rheumatoid arthritis, systemic lupus erythematosus, and polymyositis among others. Besides, enhanced postmyocardial infarction remodeling in type 1 diabetes mellitus was partially mediated by HMGB1 activation... Read More |