C3b Human
Human Plasma.
Complement C3, C3 and PZP-like alpha-2-macroglobulin domain-containing protein 1, C3, CPAMD1.
Sterile filtered solution.
Greater than 95.0% as determined by SDS-PAGE.
Description
Human Complement C3b produced in Human plasma having a molecular mass of 176 kDa.
Product Specs
C3b, a crucial component of the complement system, is generated when native C3 is cleaved by the alternative pathway C3 convertase, releasing C3a. This glycoprotein, composed of two disulfide-linked chains, is essential for the function of all three complement pathways. These pathways initiate the formation of proteolytic enzyme complexes (C3 convertases) that bind to target surfaces, cleaving C3 to release the anaphylatoxin C3a and activate C3b. A significant portion of generated C3b binds to surfaces, a crucial step in all three pathways for activating C5 and forming C5b-9 complexes, ultimately leading to target cell membrane lysis. Surface-bound C3b, along with its breakdown products iC3b and C3d, are recognized by receptors on lymphoid and phagocytic cells. This interaction through the C3b ligand triggers antigen presentation to adaptive immune cells, resulting in the expansion of target-specific B-cell and T-cell populations.
This product consists of human Complement C3b, produced from human plasma, with a molecular weight of 176 kDa.
The product is a sterile, filtered solution.
The C3b solution is prepared in a phosphate-buffered saline solution with a pH of 7.2.
Human C3b remains stable for 2-4 weeks when stored at 4°C, provided the entire vial is used within that timeframe. For extended storage, it's recommended to freeze the solution below -20°C. Adding a carrier protein like HSA or BSA (0.1%) can be beneficial for long-term storage. To maintain product integrity, avoid repeated freezing and thawing cycles.
The purity of this product is greater than 95% as determined by SDS-PAGE analysis.
Each plasma donation undergoes rigorous testing to ensure it's negative for antibodies against HIV-1, HIV-2, HCV, and the surface antigen of the Hepatitis B virus (HBSAG).
Complement C3, C3 and PZP-like alpha-2-macroglobulin domain-containing protein 1, C3, CPAMD1.
Human Plasma.
Product Science Overview
Complement C3b is derived from the cleavage of complement component 3 (C3). C3 is a glycoprotein composed of two disulfide-linked chains. When C3 is cleaved by C3 convertase enzymes, it produces two fragments: C3a and C3b . The cleavage exposes a highly reactive thioester bond in C3b, which allows it to covalently bind to pathogen surfaces .
C3b can be generated through three main pathways:
- Classical Pathway: Triggered by antibodies bound to antigens on pathogen surfaces. The C1 complex binds to these antibodies, leading to the activation of C3 convertase, which cleaves C3 into C3a and C3b .
- Alternative Pathway: C3 undergoes spontaneous hydrolysis at a low rate, producing C3b. If pathogens are present, C3b binds to their surfaces and forms a complex with Factor B, which is then cleaved by Factor D to form the C3bBb complex, a potent C3 convertase .
- Lectin Pathway: Initiated by mannose-binding lectin (MBL) binding to carbohydrate structures on pathogen surfaces, leading to the activation of C3 convertase .
- Opsonization: C3b tags pathogens, immune complexes, and apoptotic cells for phagocytosis by binding to their surfaces. This process is known as opsonization .
- Formation of C3 and C5 Convertases: C3b is involved in forming C3 convertase (C3bBb) and C5 convertase (C4b2b3b or C3bBb3b), which are crucial for the amplification of the complement cascade and the formation of the membrane attack complex (MAC) .
- Immune Clearance: Surface-bound C3b and its breakdown products (iC3b, C3d) are recognized by receptors on phagocytic and lymphoid cells, facilitating the clearance of pathogens and the stimulation of adaptive immune responses .
