PF4 – Platelet Factor 4 Antibodies
Affinity Biologicals, Inc. manufactures a broad range of PF4 – Platelet Factor 4 Antibodies which can be found in the listing below. Further information about each individual PF4 – Platelet Factor 4 antibody is available by following the associated links. Our PF4 – Platelet Factor 4 Antibodies are excellent for use in immunoassays where high sensitivity is required and are frequently the preferred reagent for immunopreciptaion techniques and activity neutralization assays. These antibodies have proven to be extremely useful in the preparation of immune-adsorbent resins for use in immuno-depletion of specific proteins from plasma as well as immuno-affinity purification of proteins. Affinity’s PF4 – Platelet Factor 4 Antibodies are manufactured for use in research applications.
Listing of PF4 – Platelet Factor 4 Antibodies
SAPF4-IG – Sheep anti human Platelet Factor 4, purified IgG (10mg vial)
SAPF4-HRP – Sheep anti human Platelet Factor 4, HRP Conjugated IgG (0.2mg vial)
SAPF4-AP – Sheep anti human Platelet Factor 4, affinity purified IgG (0.5 mg vial)
Description of PF4 – Platelet Factor 4
Platelet Factor 4 (PF4) is a small high-affinity heparin binding protein localized in the α-granules of platelets and megacaryocytes. It is a member of a multigene “intercrine-cytokine” family that includes β-thromboglobulin, connective tissue activating peptide III, monocyte-derived neutrophil chemotactic factor and melanoma growth stimulatory factor. Human PF4 consists of 70 amino acids and has a mass of 7800 daltons. In the platelet, PF4 exists as a homo-tetramer in complex with a high-molecular weight proteoglycan carrier. PF4 is one of the most abundant proteins in the platelet α-granule and is considered platelet-specific, as its concentration in platelets is more than 20,000-fold greater than in plasma. The heparin neutralization activity of PF4 is believed to be due to the presence of four lysine residues interspersed among pairs of aliphatic residues in the C-terminal region of the molecule. During vessel injury, platelets are stimulated by thrombin or other agonists to release α-granule contents at the site of injury. Presumably the potent heparin neutralization activity of PF4 would reduce the anticoagulant activity of antithrombin, prolonging the action of thrombin and activated factor X to promote clot formation. Released PF4 also binds to heparin-like molecules on the surface of endothelial cells and hepatocytes, neutralizing the anticoagulant activity expressed by these cells. Some of the other activities attributable to PF4 include the potentiation of platelet aggregation, stimulation of fibroblast attachment to substrata, chemotactic activity with respect to neutrophils and inhibition of contact activation1,2.
References and Reviews
- Rucinski B, Niewiarowski S, Strzyzewski M, Holt JC, Mayo KH; Human Platelet Factor 4 and its C-Terminal Peptides: Heparin Binding and Clearance from the Circulation; Thrombosis and Haemostasis 63, pp 493-498, 1990.
- Biochemistry and Physiology of Secreted Platelet Proteins; in Hemostasis and Thrombosis, 3rd Edition, eds. RW Colman, J Hirsh, VJ Marder and EW Salzman, pp. 546-566, J.B. Lippincott Co., Philadelphia PA, USA, 1994.