| Factor | acts on | function |
| I. Serum Proteins | ||
| C1-Inhibitor | C1r | stabilisation of C1q-r2-s2 complex, protection of catalytic domain |
| C4BP | C4b | binding of C4b, decay of C4b2a complex |
| Factor H | C3b | binding of activated serum C3b, cofactor activity für Factor I-mediated cleavage |
| Factor I | C3b/C4b | cleavage of C4b and C3b |
| Properdin | C3bBb | stabilisation of the alternative pathway C3 convertase |
| S Protein | C5b-7 | binding of soluble C5b-7 complexes to prevent spontaneous cell lysis |
| II Membrane proteins and receptors | ||
| CR1 | C3b/4b, iC3b/4b | decay of C3 and C5 convertases, cofactor activity für Factor I-mediated cleavage |
| MCP | C3b/4b | cofactor activity für Factor I-mediated cleavage |
| DAF | C4b2a, C3bBb | decay of classical and alternative C3 convertases |
| C8BP | C5b-8, C9 | prevention of MAC formation by autologous complement activation |
| CD59 | C5b-8, C9 | prevention of MAC formation by autologous complement activation |
| Legend: C4BP - C4 binding protein, CR1 - complement receptor type 1, MCP - membrane cofactor protein, DAF - decay accelerating factor, C8BP (HRF) - C8 binding protein (homologous restriction factor), CD59 (MIRL) - membrane inhibitor of reactive lysis | ||
Last update: September 20, 2000