| W factor | <biochemistry> A prosthetic group for carboxylase enzymes. Important in fatty acid biosynthesis and catabolism and has found widespread use as a covalent label for macromolecules which may then be detected by high affinity binding of labelled avidin or streptavidin. Essential growth factor for many cells. (18 Nov 1997) |
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| complement 3 nephritic factor | A magnesium-dependent IgG autoantibody found in serum of patients with chronic mesangioproliferative hypocomplementemic glomerulonephritis. It causes inactivation of c3 in the alternate pathway by cleaving c3 into two inactive fragments, c3c and c3d, instead of the normal c3b. (12 Dec 1998) |
| complement chemotactic factor | The activated complex of the fifth, sixth, and seventh components of complement (C567) which induces chemotaxis in the case of polymorphonuclear leukocytes. (05 Mar 2000) |
| complement factor h | <chemical> A beta-globulin that binds to complement 3b and makes ic3b (inactivated complement 3b) susceptible to cleavage by complement factor I. Complement factor h also acts as an alternative pathway complement inhibitor by interfering with the binding of properdin factor b to c3b. Chemical name: Complement factor H (12 Dec 1998) |
| 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) |
| 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) |