EC Number   |
General Information |
Reference |
|---|
   3.4.21.42 | physiological function |
Cls is the second enzyme in the cascade of complement activation. This enzyme can be obtained as its inactive precursor, Cls, as the fully activated proteinase, Clg, or as a subunit of the first component of complement, Cl. In addition to Clg, CI contains two other proteins: Clq and a second proteinase, Clr. Activation of Cl by immune complexes, by freeze/thaw or by incubation with calcium plus lipopolysaccharide results first in conversion of inactive Cls to the proteinase Clr |
749979 |
| 3.4.21.42 | physiological function |
enzyme C1r is active with the substrate fragment consisting of complement control protein domains, CCP1 and CCP2, plus serine protease domain of wild-type and mutant Q462N, Q462G, I464A, and Q462N/I464A forms of C1s, C1s mutant Q462N/I464A gives very low activity as substrate for C1r |
732102 |
| 3.4.21.42 | physiological function |
multiprotein complex C1 triggers the destruction of invading pathogens via lysis or by stimulation of innate and adaptive immune processes |
755267 |
| 3.4.21.42 | physiological function |
the large multicomponent assembly C1 complex, binds to immune complexes, protein modulators (e.g., C-reactive protein), and polyanionic structures on pathogens to initiate complement activation. Binding to pathogens induces a conformational change that drives activation of the zymogen proteases in stepwise fashion: C1r first autoactivates, then activates C1s (2). C1s subsequently cleaves substrates C4 and C4b-bound C2, to form the C3 convertase (C4b2a), the downstream component of the reaction cascade |
732820 |
