| Description | DAG peptide is a cyclic peptide. DAG peptide selectively recognizes a subset of astrocytes that are activated in Alzheimer's disease (AD) starting at an early stage of the disease. DAG peptide can be used as a tool to enhance the delivery of therapeutics and imaging agents to sites of vascular DAG peptide is a cyclic peptide. DAG peptide selectively recognizes a subset of astrocytes that are activated in Alzheimer's disease (AD) starting at an early stage of the disease. DAG peptide can be used as a tool to enhance the delivery of therapeutics and imaging agents to sites of vascular changes and astrogliosis in diseases associated with neuroinflammation... Read More | Inquire | 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 | Inorganic pyrophosphates are inevitably produced in the process of mRNA transcription in vitro. These substances have a great inhibitory effect on transcription. Inorganic pyrophosphatase (PPase) can hydrolyze the inorganic pyrophosphates produced in nucleic acid amplification experiments, promote Inorganic pyrophosphates are inevitably produced in the process of mRNA transcription in vitro. These substances have a great inhibitory effect on transcription. Inorganic pyrophosphatase (PPase) can hydrolyze the inorganic pyrophosphates produced in nucleic acid amplification experiments, promote the shift of reaction equilibrium to the product generation end, and increase the amount of products.The molecular weight of PPase (pyrophosphatase, inorganic, inorganic pyrophosphatase) is about 63kd, which can catalyze the hydrolysis of inorganic pyrophosphate to produce orthophosphate: P2O74_+H2O+PPase→2HPO42_. In the nucleic acid amplification experiment, PPase can hydrolyze the inorganic pyrophosphate generated with the reaction to avoid its inhibition on the reaction system. The removal of pyrophosphate can shift the reaction equilibrium to the product generation end.This product is a GMP level recombinant inorganic pyrophosphatase (yeast source) expressed by large-scale fermentation of E. coli. It is produced with raw and auxiliary materials of medicinal specifications, and the host protein residue and nucleic acid residue are strictly controlled. The product production and quality management procedures in line with GMP specifications ensure that the production process and all raw and auxiliary materials can be traced.Quality requirements project standard appearance Clear liquid Visible foreign matter Compliance with regulations PH value 7.5±8.5 activity 98U/ml-102U/ml purity ≥95% Endonuclease residues Degradation of substrate shall not exceed 10% Exonuclease residues Degradation of substrate shall not exceed 10% RNase residue Degradation of substrate shall not exceed 10% Bacterial endotoxin content ≤10EU/ml Exogenous DNA residue ≤100pg/mg Host protein residue ≤50ppm Mycoplasma detection negative Heavy metal residues ≤10ppm Follow the following specifications1. ISO 9001:2015, certified facility。2. GMP appendix - cell therapy products State Drug Administration.3. general introduction to human gene therapy - Chinese Pharmacopoeia 2020, National Pharmacopoeia Committee.4. USP chapter <1043>, adjuvant materials for cell, gene, and tissue engineered products.5. USP chapter <92>, growth factors and cytokines used in cell therapy manufacturing.6. Ph. Eur. General chapter 5.2.12, raw materials of biological origin for the production of cell-based and gene therapy medical products.Product features1. hydrolyze inorganic pyrophosphate.2. DNA synthesis: significantly enhance DNA replication ability.3. RNA synthesis: increase RNA production in in vitro transcription reaction.4. The optimal reaction temperature is 25℃, and the enzyme can be inactivated at 65℃ for 10min.Product usage1. optimize RNA transcription: improve the RNA yield of in vitro transcription reaction.2. remove PPI contamination from reagents for SNP genotyping by pyrophosphate assay.3. promote the synthesis of protein, RNA and DNA.4. catalyze the reaction of PPI + H2O → 2pi.5. ssr-pcr optimization：Improve efficiency and increase DNA production.Activity definitionCatalytic inorganic pyrophosphate formation 1 per minute under standard reaction conditions µ The amount of enzyme required for mol phosphate was defined as 1 active unit.Preservation system20 mM Tris-HCl; 100 mM NaCl; 1 mM DTT; 0.1 mM EDTA; 50% (v/v) Glycerol; pH 8.0。 Storage temperature-20±5 ℃。Matters needing attention1. the enzyme has activity in various reaction buffers. Generally, the enzyme can be directly added in HDA, lamp and other experiments.2. the dosage of the enzyme needs to be optimized in different experiments, usually adjusted at the concentration of 0.05~1u/ml.3. the optimum reaction temperature of the enzyme was 25 ℃, and it was active at 16~37 ℃, and the enzyme could be inactivated at 65 ℃ for 10min.4. cofactor: mg2+ is necessary for enzyme activity... Read More |