C3b Inactivated Mouse

Mouse C3b is derived from native purified mouse C3 upon cleavage and release of C3a with the alternative pathway C3 convertase . C3b has a molecular weight of approximately 175 kDa and is produced in mouse serum . The protein is typically formulated in a sterile filtered solution containing sodium phosphate and NaCl, with a pH of 7.2 .

C3b is central to the activation of all three pathways of complement activation . The initiation of each pathway generates proteolytic enzyme complexes (C3 convertases) that are bound to the target surface. These enzymes cleave a peptide bond in C3, releasing the anaphylatoxin C3a and activating C3b . For a brief period, this nascent C3b can react with and covalently couple to hydroxyl groups on the target surface, a process known as opsonization .

Inactivated C3b (iC3b) is formed when the thioester bond in C3b reacts with water, forming fluid-phase C3b, which is rapidly inactivated by factors H and I . The inactivated form of C3b loses its biological capabilities due to structural changes. It cannot bind factor B and therefore cannot participate in complement activation . However, it still binds to properdin and the CR3 receptor .

Research on C3b in mouse models has provided valuable insights into its mechanism of action, activity, and implications in immune function . The study of C3b and its inactivated form is crucial for understanding the dynamics of the complement system and its role in various immunological processes.