It catalyzes the proteolytic cleavage of C3 into C3a and C3b, generated during activation through the classical pathway as well as the lectin pathway. C3a is an anaphylotoxin and the precursor of some cytokines such as ASP, and C3b serves as an opsonizing agent.

C3 convertase (C4bC2b, formerly C4b2a) belongs to family of serine proteases and is necessary in innate immunity as a part of the complement system which eventuate in opsonisation of particles, release of inflammatory peptides, C5 convertase formation and cell lysis.

C3b is the larger of two elements formed by the cleavage of complement component 3, and is considered an important part of the innate immune system. C3b is potent in opsonization: tagging pathogens, immune complexes (antigen - antibody), and apoptotic cells for phagocytosis.

Mar 28, 2025 · C3 convertase activates C3 by cleaving the alpha chain, releasing C3a anaphylatoxin and generating C3b (beta chain + alpha' chain). Forms the pro-C3-convertase enzyme complex by interacting with Complement factor B Bb fragment (Bb), which is then stabilized by binding CFP, allowing the complex to become active …

Dec 12, 2006 · C3 convertase activates C3 by cleaving the alpha chain, releasing C3a anaphylatoxin and generating C3b (beta chain + alpha' chain). Forms the pro-C3-convertase enzyme complex by interacting with Complement factor B Bb fragment (Bb), which is then stabilized by binding CFP, allowing the complex to become active …

The 3 activation pathways converge into a final common pathway when C3 convertase cleaves C3 into C3a and C3b (see figure Complement Activation Pathways). C3 cleavage may result in formation of the membrane attack complex (MAC), the cytotoxic component of …

This Review provides a concise classification, summary, and interpretation of the more than 50 unique crystal structure determinations for human C3. It also highlights other salient features of C3 structure that were made possible through solution-based methods, including Hydrogen/Deuterium Exchange and Small Angle X-ray Scattering.

All three of the complement classical, lectin, and alternative activation pathways lead to the cleavage of C3a from C3 to form active C3b, which attaches covalently to cell surfaces through a thioester bridge (1, 2).

2 days ago · A subset of the intracellular C3 is tonically cleavage-processed by the protease cathepsin L (CTSL) into bio-active C3a and C3b (Figure 2). The C3a thus generated engages the lysosomal-expressed C3aR, which drives activation of the nutrient sensor mammalian target of rapamycin (mTOR) as well as the low-level glycolysis required for peripheral T ...

Dec 31, 2013 · They showed that resting human T cells express mRNA encoding cathepsin L (CTSL), and that CTSL cleaves C3 into biologically active C3a and C3b fragments in vitro. C3 and CTSL were found to...