| complement factor I | <enzyme> Serine proteinase that acts on ic3b (inactivated complement 3b) to cleave it into c3c and c3dg with the help of a trypsin-like proteolytic enzyme. Complement factor I was formerly called kaf, c3binf, or enzyme 3b inactivator. Registry number: EC 3.4.21.45 (12 Dec 1998) |
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| mouse antialopecia factor | A member of the vitamin B complex necessary for growth of yeast and of mice, absence from the diet causes hair loss and dermatitis in mice. (27 Sep 1997) |
| plasma factor X | <chemical> Storage-stable blood coagulation factor acting in the intrinsic pathway. Its activated form, ixa, forms a complex with factor viii and calcium on platelet factor 3 to activate factor x to xa. Deficiency of factor ix results in christmas disease (haemophilia b). Chemical name: Blood-coagulation factor IX (12 Dec 1998) |
| plasma labile factor | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| Williams factor | high molecular weight kininogen |
| M phase promoting factor | Protein whose levels rise rapidly just before and fall away just after, mitosis. Thought to be a trigger for mitosis. (18 Nov 1997) |
| plasma thromboplastin factor | A coagulation (clotting) factor. Classic haemophilia (haemophilia A) is due to a congenital deficiency in the amount (or activity) of factor VIII. Factor VIII is also known as antihemophiliac factor (AHF) or antihemophiliac globulin (AHG). The gene for factor VIII (that for classic haemophilia) is on the X chromosome so females can be silent carriers without symptoms and males can be haemophiliacs. (12 Dec 1998) |
| plasma thromboplastin factor B | <chemical> Storage-stable blood coagulation factor acting in the intrinsic pathway. Its activated form, ixa, forms a complex with factor viii and calcium on platelet factor 3 to activate factor x to xa. Deficiency of factor ix results in christmas disease (haemophilia b). Chemical name: Blood-coagulation factor IX (12 Dec 1998) |
| plasmin prothrombins conversion factor | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| platelet-activating factor | <cytokine> Potent phospholipid activator and mediator of many leucocyte functions, including platelet aggregation, inflammation, and anaphylaxis. It is produced in response to specific stimuli by a variety of cell types, including neutrophils, basophils, platelets, and endothelial cells. Several molecular species of platelet-activating factor have been identified which vary in the length of the O-alkyl side chain. It is an important mediator of bronchoconstriction. Synonym: platelet-aggregating factor. Acronym: PAF (20 Sep 2002) |
| platelet-aggregating factor | <cytokine> Potent phospholipid activator and mediator of many leucocyte functions, including platelet aggregation, inflammation, and anaphylaxis. It is produced in response to specific stimuli by a variety of cell types, including neutrophils, basophils, platelets, and endothelial cells. Several molecular species of platelet-activating factor have been identified which vary in the length of the O-alkyl side chain. It is an important mediator of bronchoconstriction. Synonym: platelet-aggregating factor. Acronym: PAF (20 Sep 2002) |
| platelet-derived growth factor | <growth factor> The major mitogen in serum for growth in culture of cells of connective tissue origin. It consists of 2 different but homologous polypeptides A and B (~30,000 D) linked by disulphide bonds. Believed to play a role in wound healing. It is carried in the alpha-granules of platelets and is released when platelets adhere to traumatised tissues. Connective tissue cells near the traumatised region respond by initiating the process of replication. The B chain is almost identical in sequence to p28sis, the transforming protein of simian sarcoma virus, that can transform only those cells that express receptors for platelet derived growth factor, suggesting that transformation is caused by autocrine stimulation. The receptor is a tyrosine kinase. Acronym: PDGF (12 Dec 1998) |
| platelet factor 3 | <haematology> Phospholipid associated with the platelet plasma membrane that contributes to the blood clotting cascade by forming a complex (thromboplastin) with other plasma proteins and activating prothrombin. (31 Dec 1997) |
| platelet factor 4 | <haematology> Platelet released protein that promotes blood clotting by neutralising heparin. (31 Dec 1997) |
| platelet tissue factor | <haematology> Traditional name for substance in plasma that converts prothrombin to thrombin. Now known not to be a single substance. (See thrombin). (18 Nov 1997) |