Complement C3 (C3 and PZP-like alpha-2-macroglobulin Domain-containing Protein 1, C3, CPAMD1) (Biotin)

Human Complement C3 is encoded by gene located 19p13.3-p13.2. C3, C4 and C5 are strikingly similar suggesting a common evolutionary origin. C3 is an acute phase reactant. Synthesis of C3, a glycoprotein, is induced during acute inflammation. The liver is the main site of synthesis, although small amounts are also produced by activated monocytes and macrophages. A single chain precursor (pro-C3) of ~200kD is found intracellularly; the cDNA shows that it comprises 1663aa. This is processed by proteolytic cleavage into alpha (~115kD) and beta subunits (~75kD) which in the mature protein are linked by disulfide bonds. Pro-C3 contains a signal peptide of 22aa residues, the beta chain (645 residues) and the alpha chain (992 residues). The 2 chains are joined by 4 arginine residues that are not present in the mature protein. Human C3 has 79% identity to mouse C3 at the nucleotide level and 77% at the aa level. Human C3 concentration in normal human serum is ~1.25mg/ml. Classical and alternative activation pathways of complement converge at C3 step. Activation via either pathway can result in assembly of C3-cleaving enzymes (C3 convertases) on target surfaces. Both C3 convertases cleave the C3 a-chain at peptide bond 77 resulting in production of C3a (MW: 9083) and C3b fragments (MW: 80,000). Released C3a peptide is one of the three complement anaphylatoxins. The nascent C3b fragment can form a covalent ester bond with target surface. This covalent attachment of C3b to target acceptors is required for continuation of complement activation. C3 nephritic factor, an IgG antibody against complement components, is demonstrable in some cases of partial lipodystrophy. C3-deficient homozygotes developed mesangiocapillary glomerulonephritis. Applications: Suitable for use in ELISA and Western Blot. Other applications not tested. Recommended Dilutions: ELISA: 1:5000-1:30,000 Western Blot: 1:2000-1:10,000 Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.