Activating Compound | Comment | Organism | Structure |
---|---|---|---|
C4b binding protein | C4BP, required for activity, dependent on | Homo sapiens | |
factor H | required for activity, dependent on | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
D104S | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
D385N/K387S | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
D420N/N422T | site-directed mutagenesis, the mutation in the serine protease domain decreases the binding of the enzyme to substrate analogue C3met | Homo sapiens |
D497N | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
F82N/N84T | site-directed mutagenesis, the mutation in the FIMAC domain impairs enzyme activity, which is rescued by deglycosylation of the mutant | Homo sapiens |
K124N | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
K182N/R184S | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
K326N/A328T | site-directed mutagenesis, the mutation in the serine protease domain decreases the binding of the enzyme to substrate analogue C3met | Homo sapiens |
K458N/N460T | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
L171N | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
additional information | mutations in the FIMAC, CD5, and LDLr1 domains do not decrease the binding of the enzyme to substrate analogues C3met or C4met | Homo sapiens |
N404T | site-directed mutagenesis, the mutation in the serine protease domain decreases the binding of the enzyme to substrate analogues C3met and C4met | Homo sapiens |
Q210N/V212T | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
Q219N/K221S | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
Q242N/K244S | site-directed mutagenesis, the mutation in the LDLr2 domain decreases the binding of the enzyme to substrate analogues C3met and C4met | Homo sapiens |
Q257N/Q259S | site-directed mutagenesis, the mutation in the LDLr2 domain decreases the binding of the enzyme to substrate analogues C3met and C4met | Homo sapiens |
R35N/I37T | site-directed mutagenesis, the mutation in the FIMAC domain impairs enzyme activity, which is rescued by deglycosylation of the mutant | Homo sapiens |
R365N | site-directed mutagenesis, the mutation in the serine protease domain decreases the binding of the enzyme to substrate analogues C3met and C4met | Homo sapiens |
R61N | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
S561N/Y563T | site-directed mutagenesis, the mutation in the serine protease domain impairs enzyme activity, which is rescued by deglycosylation of the mutant | Homo sapiens |
T54N/V56T | site-directed mutagenesis, altered kinetics compared to the wild-type | Homo sapiens |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
additional information | the enzyme does not have any known physiological inhibitor, although synthetic inhibitors, such as suramin, are able to weakly inhibit it | Homo sapiens | |
suramin | weak inhibition | Homo sapiens |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
extracellular | the enzyme circulates in the blood | Homo sapiens | - |
- |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
38000 | - |
1 * 50000 + 1 * 38000, SDS-PAGE, the enzyme is proteolytically processed into the heavy and the light chain that remain covalently linked by a disulfide bond, domains structure overview | Homo sapiens |
50000 | - |
1 * 50000 + 1 * 38000, SDS-PAGE, the enzyme is proteolytically processed into the heavy and the light chain that remain covalently linked by a disulfide bond, domains structure overview | Homo sapiens |
66000 | - |
nonglycosylated proenzyme | Homo sapiens |
88000 | - |
mature enzyme | Homo sapiens |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
- |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
glycoprotein | factor I is a multidomain acute phase glycoprotein, that is N-glycosylated at six positions (25-27%, w/w) with heavily sialylated biantennary glycans. Three-dimensional overview of the glycosylation sites. Deglycosylation by endoglycosidases, profile overview | Homo sapiens |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
blood | the enzyme circulates in a zymogen-like state in blood | Homo sapiens | - |
additional information | the enzyme is produced mainly in the liver but also by monocytes, fibroblasts, keratinocytes, and endothelial cells | Homo sapiens | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
Boc-Asp(benzyl)-Pro-Arg-4-methylcoumarin 7-amide + H2O | - |
Homo sapiens | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
dimer | 1 * 50000 + 1 * 38000, SDS-PAGE, the enzyme is proteolytically processed into the heavy and the light chain that remain covalently linked by a disulfide bond, domains structure overview | Homo sapiens |
Synonyms | Comment | Organism |
---|---|---|
factor I | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.4 | - |
assay at | Homo sapiens |
General Information | Comment | Organism |
---|---|---|
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 | Homo sapiens |