C3konvertaseja

C3konvertaseja refers to an enzyme complex crucial for the complement system, a vital part of the innate immune response. This complex is responsible for cleaving the third component of complement, C3, into two active fragments: C3a and C3b. The formation and activity of C3konvertaseja are central to the amplification of the complement cascade.

There are two primary pathways that lead to the formation of C3konvertaseja: the alternative pathway and the classical/lectin pathways. In the alternative pathway, a spontaneous C3 hydrolysis product, C3b, can bind to a target surface and then associate with Factor B. Factor D then cleaves Factor B, forming the C3konvertaseja of the alternative pathway, C3bBb. This complex continuously cleaves more C3, amplifying the process.

The classical and lectin pathways also generate C3konvertaseja. In these pathways, antibody-antigen complexes (classical) or carbohydrate structures on pathogens recognized by lectins (lectin pathway) initiate a cascade involving C1, C2, and C4. The resulting complex, C4b2a, is the C3konvertaseja for these pathways.

Once formed, C3konvertaseja cleaves C3, leading to the generation of C3a and C3b. C3b can covalently attach to the surface of pathogens or host cells, marking them for phagocytosis (opsonization) or contributing to the formation of the membrane attack complex (MAC). C3a is an anaphylatoxin, involved in recruiting immune cells to the site of infection and promoting inflammation. The precise regulation of C3konvertaseja activity is essential to prevent damage to host tissues.