Summary for peptidase S01.199: complement factor I

Summary Gene structure Alignment Tree Sequences Sequence features Distribution Structure Literature Human EST Mouse EST Substrates


MEROPS Namecomplement factor I
Other namesC3bINA, complement component C3b inactivator, C3b/C4b inactivator
Domain architecture
MEROPS Classification
Classification Clan PA >> Subclan PA(S) >> Family S1 >> Subfamily A >> S01.199
Holotypecomplement factor I (Homo sapiens), Uniprot accession P05156 (peptidase unit: 340-576), MERNUM MER0000228
History Identifier created: Handbook of Proteolytic Enzymes (1998) Academic Press, London.
Catalytic typeSerine
PeplistIncluded in the Peplist with identifier PL00304
NC-IUBMBSubclass 3.4 (Peptidases) >> Sub-subclass 3.4.21 (Serine endopeptidases) >> Peptidase
EnzymologyBRENDA database
Proteolytic eventsCutDB database (7 cleavages)
Activity statushuman: active (Sim, 2004)
mouse: active (by similarity to human) (Jiang & Molina, 2000)
PhysiologyFactor I has very restricted specificity, cleaving only complement components C3b or C4b in the presence of a cofactor such as factor H (Tsiftsoglou et al., 2005). Rare deficiency in human predisposes to bacterial infection.
Pathways KEGGStaphylococcus aureus infection
Other databases WIKIPEDIA
Human genetics
Gene symbol Locus Megabases Ensembl Entrez gene Gene Cards OMIM
CFI 4q24-q25 ENSG00000138799 3426 IF 217030
Mouse genetics
Gene symbol Position Megabases Ensembl Entrez gene MGI
Cfi 3:G3 ENSMUSG00000028000 12630 MGI:105937