EC Number   |
General Information |
Reference |
|---|
   3.4.21.45 | malfunction |
mutations in complement factor I affect both secretion and function of complement factor I, which leads to impaired regulation of the complement system in atypical hemolytic uremic syndrome |
708380 |
| 3.4.21.45 | malfunction |
two mutations, G17V and C196S, in the enzyme are identified in patients, which result in failure to secrete the enzyme, phenotype with high C3, membrane attack complex, and interleukin-1 levels in the brain and perivascular hemorrhagic necrosis, subacute inflammation in the subcortical white matter, patchy demyelination and an inflammatory infiltrate with a neutrophilic and histiocytic predominance, overview. Mutations of complement factor I and potential mechanisms of neuroinflammation in acute hemorrhagic leukoencephalitis, overview |
732231 |
| 3.4.21.45 | more |
the enzyme can be selectively bound by Prevotella intermedia ATCC 25611 cells, the bound enzyme retains its serine protease activity, interaction analysis, overview |
732690 |
| 3.4.21.45 | more |
the Nipah virus is completely resistant to in vitro neutralization by normal human serum |
732425 |
| 3.4.21.45 | physiological function |
factor I is a serine protease that inhibits all complement pathways by degrading activated complement components C3b and C4b. It functions only in the presence of several cofactors, such as factor H, C4b-binding protein, complement receptor 1, and membrane cofactor protein |
732047 |
| 3.4.21.45 | physiological function |
factor I is in a proteolytically inactive form, it circulates in a zymogen-like state despite being fully processed to the mature sequence. This inactive form is maintained by the noncatalytic heavy-chain allosterically modulating activity of the light chain. Once the ternary complex of factor I, a cofactor and a substrate is formed, the allosteric inhibition is released, and factor I is oriented for cleavage. General model for factor I regulation of complement predicts that binding of the cofactor to C3b produces a stable platform onto which the factor I can dock, binding of factor I releases the allosteric inhibitory effects of the heavy chain and induces remodeling of the zymogen-activation domain and the active site forms around the substrate loop for the primary cleavage event |
718324 |
| 3.4.21.45 | physiological function |
the enzyme plays an important role in Cynoglossus semilaevis immunity and shows broad-spectrum antimicrobial activities against the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and Shewanella putrefaciens |
753374 |
| 3.4.21.45 | physiological function |
the factor I activity in Nipah virus inhibits human complement pathways through cleavage of C3b |
732425 |
| 3.4.21.45 | physiological function |
the interaction of clumping factor A with factor I contributes to Staphylococcus aureus virulence by a complement-mediated mechanism |
708715 |
| 3.4.21.45 | physiological function |
the serine protease Factor I (FI) is the central inhibitor of complement degrading complement components C3b and C4b in the presence of cofactors such as C4b binding protein (C4BP) and factor H (FH). The selective enzyme binding by the bacterium Prevotella intermedia in human serum represents a distinct mechanism contributing to complement evasion by a Gram-negative bacterial pathogen associated with chronic diseases. Binding of enzyme cofactors C4BP and FH by Prevotella intermedia ATCC 25611 leads to increased degradation of C4b and C3b, respectively |
732690 |
