EC Number   |
Natural Substrates |
|---|
   3.4.21.47 | C2 fragment + H2O |
C-terminal fragment originating from the processing of meningococcal proteases |
| 3.4.21.47 | complement component C3 + H2O |
- |
| 3.4.21.47 | complement component C3 + H2O |
complement component C3 is the preferred substrate. Cleavage of the preferred C3 substrate and deposition of C3b effectively switches the output of the enzyme from C3b to C5b, resulting in initiation of the cytosolic process of complement |
| 3.4.21.47 | complement component C3 zymogen + H2O |
activation |
| 3.4.21.47 | complement component C5 + H2O |
- |
| 3.4.21.47 | complement component C5 zymogen + H2O |
activation |
| 3.4.21.47 | more |
the enzyme is involved in the alternative pathway of human complement |
| 3.4.21.47 | more |
the activation peptide, C5a, possesses potent spasmogenic and chemotactic activity |
| 3.4.21.47 | more |
the enzyme has a very short half-life. Dissociation of the two noncovalently bound subunits proceeds with a half-life of 1-3 min at 37°C under physiological conditions, and this rate increases greatly if regulatory proteins are present. Numerous decay-accelerating proteins are present in plasma and on host cells that bind to the noncatalytic subunit C3b and increase the rate at which the catalytic subunit Bb is released into the medium. Bb loses its enzymatic activity and its ability to bind to C3b upon release. Although C3b is able to rebind Bb and reform the enzyme, the interaction with most decay-accelerating factors also leads to permanent proteolytic interaction of the cell-bound subunit C3b by a fluid-phase protease Factor I. These regulatory events limit cleavage of C3, reduce release of the anaphylatoxin C3a and control the formation of more efficient C5 convertase enzymes |
| 3.4.21.47 | neisserial heparin binding antigen + H2O |
also known as GNA2132 (genome-derived Neisseria antigen 2132) |
