Factor IX
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coagulation factor IX
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Identifiers | |
Symbol | F9 |
HUGO | 3551 |
Entrez | 2158 |
OMIM | 306900 |
RefSeq | NM_000133 |
UniProt | P00740 |
Other data | |
EC number | 3.4.21.22 |
Locus | Chr. X q26.3-q27.1 |
Factor IX (or Christmas factor or Christmas-Eve factor) is one of the serine proteases (EC 3.4.21.22) of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes hemophilia B.
Contents[hide] |
[edit] Physiology
Factor IX is inactive unless activated by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, it acts by hydrolysing one arginine-isoleucine bond in factor X to form factor Xa. It requires calcium, membrane phospholipids, and factor VIII as cofactors to do so.
[edit] Genetics
The gene for factor IX is located on the X chromosome (Xq27.1-q27.2). It was first cloned in 1982 by Kotoku Kurachi and Earl Davie.[1]
[edit] Role in disease
Deficiency of factor IX causes Christmas disease (hemophilia B). Over 100 mutations of factor IX have been described; some cause no symptoms, but many lead to a significant bleeding disorder.
[edit] Reference
- ^ Kurachi K, Davie E (1982). "Isolation and characterization of a cDNA coding for human factor IX". Proc Natl Acad Sci U S A 79 (21): 6461-4. PMID 6959130.
Trypsin - Chymotrypsin - Elastase (Neutrophil, Pancreatic) - Enteropeptidase
Acrosin - Pronase - Proprotein convertases (1, 2) - Subtilisin/Furin
Immune (Chymase, Granzyme, Tryptase, Proteinase 3/Myeloblastin) - Venombin (Ancrod, Batroxobin)
Complement system: Factor B - Factor D - Factor I - MASP (MASP1, MASP2)
Coagulation factors: Thrombin - Factor VIIa - Factor IXa - Factor Xa - Factor XIa - Factor XIIa - Kallikrein (PSA) - Fibrinolysis: Plasmin - Tissue plasminogen activator - Urinary plasminogen activator