Factor IX (F9) Rat Protein

This gene encodes vitamin K-dependent coagulation factor IX that circulates in the blood as an inactive zymogen. This factor is converted to an active form by factor XIa, which excises the activation peptide and thus generates a heavy chain and a light chain held together by one or more disulfide bonds. The role of this activated factor IX in the blood coagulation cascade is to activate factor X to its active form through interactions with Ca+2 ions, membrane phospholipids, and factor VIII. Alterations of this gene, including point mutations, insertions and deletions, cause factor IX deficiency, which is a recessive X-linked disorder, also called hemophilia B or Christmas disease. [provided by RefSeq, Jul 2008]

F9: Factor IX is a vitamin K-dependent plasma protein that participates in the intrinsic pathway of blood coagulation by converting factor X to its active form in the presence of Ca(2+) ions, phospholipids, and factor VIIIa. Defects in F9 are the cause of recessive X-linked hemophilia B (HEMB); also known as Christmas disease. Mutations in position 43 (Oxford-3, San Dimas) and 46 (Cambridge) prevents cleavage of the propeptide, mutation in position 93 (Alabama) probably fails to bind to cell membranes, mutation in position 191 (Chapel-Hill) or in position 226 (Nagoya OR Hilo) prevent cleavage of the activation peptide. Defects in F9 are the cause of thrombophilia due to factor IX defect (THPH8). A hemostatic disorder characterized by a tendency to thrombosis. Belongs to the peptidase S1 family.

Protein type: EC 3.4.21.22; Protease; Secreted, signal peptide; Secreted

Chromosomal Location of Human Ortholog: Xq27.1-q27.2

Cellular Component: Golgi lumen; endoplasmic reticulum lumen; extracellular region; plasma membrane

Molecular Function: serine-type endopeptidase activity; calcium ion binding

Biological Process: blood coagulation, extrinsic pathway; cellular protein metabolic process; blood coagulation; post-translational protein modification; proteolysis; peptidyl-glutamic acid carboxylation; blood coagulation, intrinsic pathway

Disease: Hemophilia B; Thrombophilia, X-linked, Due To Factor Ix Defect; Coumarin Resistance