| Description | Complement C3 (C3) is the most abundant component of the complement system, with levels in human plasma of ~1.2-1.5 mg/ml. It is central to the activation of both the classical and alternative complement pathways, both of which lead to the proteolytic processing of C3 to C3a and C3b. C3 exists as a Complement C3 (C3) is the most abundant component of the complement system, with levels in human plasma of ~1.2-1.5 mg/ml. It is central to the activation of both the classical and alternative complement pathways, both of which lead to the proteolytic processing of C3 to C3a and C3b. C3 exists as a heterodimer with molecular masses of 115 kDa and 75 kDa, although it is readily processed to create C3a, C3b or C3c depending on the processed state.Reacts to C3 antisera on Western BlotNegative against C4 antisera on Western BlotRef: Tack BF and JW Prahl. 1976. Biochemistry. 15:4513, Tack BF et al. 1981. Methods Enzymol. 80:64, Janatova, J. 1988. Methods Enzymol. 162:579... Read More | Protein Purity>95% by SDS-PAGEExtinction Coeff.A276 nm = 0.456 at 1.0 mg/mLMolecular Weight8,759 Da (single chain)General DescriptionNatural human C4a is prepared by cleavage of human C4 protein by human C1s. It is produced during activation of both the classical and lectin pathways of complementProtein Purity>95% by SDS-PAGEExtinction Coeff.A276 nm = 0.456 at 1.0 mg/mLMolecular Weight8,759 Da (single chain)General DescriptionNatural human C4a is prepared by cleavage of human C4 protein by human C1s. It is produced during activation of both the classical and lectin pathways of complement. C4a is a member of the anaphylatoxin family of three proteins (C3a, C4a and C5a) produced by the activation of complement (Hugli, T.E. et al. (1981)). It is an unglycosylated polypeptidecontaining 77 amino acids with a molecular mass of 8,759 daltons. Many of the biological functions of C4a are similar to those of C3a, but the specific activities are far below those of C3a. C4a activity is so low, in fact, that it was initially thought to be inactive. These measured activities include inducing muscle contraction in the guinea pig ileum test (spasmogenic activity), desensitization of muscle to C3a stimulation suggesting that the same receptor for both C3a and C4a is involved (tachyphylactic activity) and inducing vascular permeability in human skin (Gorski J.P. et al. (1979)). C4a does not show tachyphylactic activity against C5a or chemotactic activity. Removal of the C-terminal arginine by serum carboxypeptidase N destroys all these activities (Meuller-Ortiz, S.L., et al. (2009)). C4a appears to act through the C3a receptor (C3aR) which is a G-protein coupled receptor found widely distributed on peripheral tissues, lymphoid cells (neutrohphils, monocyes, and eosinophils) and in the central nervous system (astrocytes, neurons and glial cells) (Law, S.K.A. and Reid, K.B.M. (1995)). Physical Characteristics & StructureMolecular weight: 8,759 calculated molecular mass. Observed mass (MALDI-TOF) is 8,762 + 9 mass units. pI = 9.0 to 9.5 (Gorski, J.P. et al. (1981))Amino acid sequence (77 amino acids): NVNFQKAINE KLGQYASPTA KRCCQDGVTR LPMMRSCEQR AARVQQPDCR EPFLSCCQFA ESLRKKSRDK GQAGLQRC4a is thought to be structurally very similar to C3a and C5a to which it is homologous. Thus its 3D structure is probably similar to the X-ray-derived crystal structureof C3a (Huber, R. et al. (1980)) and the NMR derived structure of C3a: Nettesheim, D.G. et al. (1988); Murray, I. et al. (1999).FunctionSee General Description above. C4a exhibits much weaker biological activities than C3a and C5a. Its activity in inducing erythema and edema in human skin is 25,000-fold weaker than that of C5a and 100-fold weaker than C3a per nanomole. The spasmogenic activity of C4a is 2000-fold weaker than C5a and 100-fold weaker than that of C3a. Due to these differences the role of C4a in these responses in vivo is thought to be negligible.AssaysTwo well established assays for C4a and C3a functional activities include induction of contraction in the guinea pig ileum and the permeation of a dye such as trypan blue from the vasculature into skin. The anaphylatoxins also induce mast cell degranulation, (measured as histamine release), platelet aggregation, IL-1 release from monocytes and the release of prostaglandins and leukotrienes from many cells and tissues. The other assays used for C3a (Dodds, A.W. and Sim, R.B. (1997)) should also respond to C4a, but few reports have described utilizing these assays with C4a. ELISA kits for the assay of C4a levels (or more correctly C4a desArg levels) in blood and other fluids are sold by several companies. These measurements are useful for detecting complement activation in vivo, but the interpretation of their meaning is complicated by the fact that clearance of the anaphylatoxins is rapid. In vivoFreshly drawn normal human serum contains significant levels of all three anaphylatoxins. Although these may represent the resting concentration in vivo it is difficult to draw or store blood without some complement activation so a true in vivo concentration is difficult to determine. The presence of EDTA and Futhan in the collection tubes can minimize this background (Pfeifer, P.H. et al. (1999)). Full activation of all C4 in blood (600µg/mL) would result in ~3,400 nM C4a (~30 µg/mL). Due to the low biological activity of C4a it could require activation of most of the C4 in a small region to achieve the micromolar C4a concentrations necessary to elicit a response.RegulationC4a levels are regulated by three processes: formation, inactivation and clearance. There are two enzymes that cleave C4 and release C4a: C1s and MASP-2. C4a is “inactivated” by removal of its C-terminal arginine amino acid. The product C4a desArg (or C4a without the C-terminal arginine) is produced by the action of the plasma enzyme carboxypeptidase N (Mueller-Ortiz S.L. et al. (2009)). The inactivation is rapid and most C4a is converted to C4a desArg within minutes of its formation. Inactivated C4a lack measurable biological activity. Because of the large number of cells bearing C3a/C4areceptors (endothelial, immune, smooth muscle, neuronal, etc.) the capture, internalization and digestion of C4a and C4a desArg probably results in its removal from circulation.DeficienciesA deficiency of C4 or a deficiency of all of the enzymes that cleave C4 to generate C4a could result in the absence of C4a. There are no known complete deficiencies of all ofthe C4 cleaving enzymes. Examples of C4 deficient humans and mice exist (Wessels, M.R. et al. (1995)), but the degree to which pathologies associated with C4 deficiency are due to the lack of C4 or the absence of C4a is unclear. DiseasesThere are no known diseases connected to C4a or C4a desArg. Precautions/Toxicity/HazardsThe source of C4a is human serum, therefore appropriate precautions must be observed 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.Injection can cause anaphylatic shock which is a generalized circulatory collapse similar to that caused by an allergic reaction.Hazard Code: B WGK Germany 3... Read More | Inquire | Protein kinase inhibitor 1 hydrochloride is a potent HIPK2 inhibitor, with IC 50 s of 136 and 74 nM for HIPK1 and HIPK2, and a K d of 9.5 nM for HIPK2.In VitroProtein kinase inhibitor 1 hydrochloride is a potent HIPK2 inhibitor, with IC 50 s of 136 and 74 nM for HIPK1 and HIPK2, and a K d of 9.5 nM Protein kinase inhibitor 1 hydrochloride is a potent HIPK2 inhibitor, with IC 50 s of 136 and 74 nM for HIPK1 and HIPK2, and a K d of 9.5 nM for HIPK2.In VitroProtein kinase inhibitor 1 hydrochloride is a potent HIPK2 inhibitor, with IC 50 s of 136 and 74 nM for HIPK1 and HIPK2, and a K d of 9.5 nM for HIPK2. Protein kinase inhibitor 1 (Compound A64) is not an effective Cdk1 inhibitor (IC 50 > 10 µM). A64 is moderately selective across a panel of kinases, with K d s of 3.7 nM (PIM3), 6.1 nM (CSNK2A2), 6.1 nM (CSNK2A2), 8.8 nM (DYRK1A), 9.5 nM (DAPK1), 31 nM (CSNK2A1), 37 nM (PIM1), 130 nM (DRAK2), 150 nM (CLK2), 190 nM (DRAK1), 220 nM (ULK2), 240 nM (CLK1), 250 nM (DYRK2), and 390 nM (ERK8) and IC 50 s of 19 nM (DYRK1A), 62 nM (DYRK1B), and 74 nM (HIPK2). MCE has not independently confirmed the accuracy of these methods. They are for reference only.IC50& Target:DYRK1 DYRK2... Read More | Purity:>95%, by SDS-PAGE visualized with Coomassie® Blue StainingDescription:MCP-2 and CCL7 are two monocyte chemotactic proteins produced by human MG-63 osteosarcoma cells. Both MCP-2 and CCL7 are members of the C-C family of chemokines and share 62% and 71% amino acid sequence identity, Purity:>95%, by SDS-PAGE visualized with Coomassie® Blue StainingDescription:MCP-2 and CCL7 are two monocyte chemotactic proteins produced by human MG-63 osteosarcoma cells. Both MCP-2 and CCL7 are members of the C-C family of chemokines and share 62% and 71% amino acid sequence identity, respectively, with MCP-1. CCL7 also shares 58% amino acid identity with MCP-2. CCL7 cDNA encodes a 99 amino acid residue precursor protein from which the N-terminal 23 amino acid residues are cleaved to generate the 76 amino acid residue mature CCL7. Mature CCL7 contains a potential N-linked and several possible O-linked glycosylation sites. Similarly to other C-C chemokines, all three MCP proteins are monocyte chemoattractants. In addition, the three MCPs can chemoattract activated NK cells as well as CD4+ and CD8+ T lymphocytes. All three cytokines have also been shown to attract eosinophils and induce histamine secretion from basophils... Read More |