Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. In contrast to most other coagulation factors, it is not enzymatically active but functions as a cofactor. Deficiency leads to predisposition for hemorrhage, while some mutations (most notably factor V Leiden) predispose for thrombosis. Hugo is a masculine name. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... The National Center for Biotechnology Information (NCBI) is part of the US National Library of Medicine (NLM), which is a branch of the US National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... Short and long arms Chromosome. ... Chromosome 1 is, by convention, the designation for the largest human chromosome. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Coagulation is a complex process by which blood forms solid clots. ... A cofactor is the following: In mathematics a cofactor is the minor of an element of a square matrix. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Factor V Leiden (sometimes Factor VLeiden) is the name given to a variant of human factor V that causes a hypercoagulability disorder. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ...

Genetics

The gene for factor V is located on the first chromosome (1q23). It is genomically related to the family of multicopper oxidases, and is homologous to coagulation factor VIII. The gene spans 70 kB, consists of 25 exons, and the resulting protein has a relative molecular mass of approximately 330000. For a non-technical introduction to the topic, see Introduction to Genetics. ... Figure 1: A representation of a condensed eukaryotic chromosome, as seen during cell division. ...

Physiology

Factor V circulates in plasma as a single-chain molecule with a plasma half-life of about 12 hours. Half-lives up to 36 hours have been reported, though.

Factor V is able to bind to activated platelets and is activated by thrombin. On activation, factor V is spliced in two chains (heavy and light chain with molecular masses of 110000 and 73000, respectively) which are nonconvalently bound to each other by calcium. Factor V is active as a cofactor of the thrombinase complex. The activated factor X (FXa) enzyme requires Ca⁺⁺ and activated factor V to convert prothrombin to thrombin on the cell surface membrane. This is considered part of the common pathway in the coagulation cascade. A 250 ml bag of newly collected platelets. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Calcium plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. ... Factor X, also known by the eponym Stuart-Prower factor or as thrombokinase, is an enzyme ( EC 3. ... Calcium plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ...

Factor Va is degraded by activated protein C, one of the principal physiological inhibitors of coagulation. In the presence of thrombomodulin, thrombin acts to decrease clotting by activating Protein C; therefore, the concentration and action of protein C are important determinants in the negative feedback loop through which thrombin limits its own activation. Protein C is a major physiological anticoagulant. ... Thrombomodulin is an integral membrane protein expressed on the surface of epithelial cells. ...

Role in disease

Various hereditary disorders of factor V are known. Deficiency is associated with a rare mild form of hemophilia (termed parahemophilia or Owren parahemophilia), the incidence of which is about 1:1,000,000. It inherits in an autosomal recessive fashion. Haemophilia or hemophilia is the name of any of several hereditary genetic illnesses that impair the bodys ability to control bleeding. ... In genetics, the term recessive gene refers to an allele that causes a phenotype (visible or detectable characteristic) that is only seen in a homozygous genotype (an organism that has two copies of the same allele). ...

Other mutations of factor V are associated with venous thrombosis. They are the most common hereditary causes for thrombophilia (a tendency to form blood clots). The most common one of these, factor V Leiden, is due to the replacement of an arginine residue with glutamine at amino acid position 506 (R506Q). All prothrombotic factor V mutations (factor V Leiden, factor V Cambridge, factor V Hong Kong) make it resistant to cleavage by activated protein C ("APC resistance"). It therefore remains active and increases the rate of thrombin generation. It has been suggested that mutant be merged into this article or section. ... A venous thrombosis is a blood clot that forms within a vein. ... Thrombophilia is the propensity to develop thrombosis (blood clots) due to an abnormality in the system of coagulation. ... A thrombus is the final product of blood coagulation, through the aggregation of platelets and the activation of the humoral coagulation system. ... Factor V Leiden (sometimes Factor VLeiden) is the name given to a variant of human factor V that causes a hypercoagulability disorder. ... Arginine (symbol Arg or R) is an α-amino acid. ... Glutamine is one of the 20 amino acids encoded by the standard genetic code. ...

History

It was discovered in 1947 by Dr Paul Owren (1905-1990). The complete amino acid sequence of the protein was published in 1987 by Jenny et al.

Reference

• Jenny RJ, Pittman DD, Toole JJ, Kriz RW, Aldape RA, Hewick RM, Kaufman RJ, Mann KG. Complete cDNA and derived amino acid sequence of human factor V. Proc Natl Acad Sci U S A. 1987;84:4846-50. PMID 3110773.

External Links

• The Coagulation Factor V Protein