Platelet Factor 4 (PF4) is a small high-affinity heparin binding protein localized in the alpha-granules of platelets and megacaryocytes.
It is a member of a multigene “intercrinecytokine” family that includes beta-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 7800dD.
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 alpha-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 alpha-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.
Applications:Suitable for use in Immunoelectrophoresis and ELISA.
Other applications not tested.
Recommended Dilution:Optimal dilutions to be determined by the researcher.
Storage and Stability:May be stored at 4°C for short-term only.
Aliquot to avoid repeated freezing and thawing.
Store at -20°C.
Aliquots are stable for 12 months after receipt.
For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：1mg
Host：sheep
Source Antibody：human
Grade：Purified
Purity：Purified by caprylic acid and ammonium sulfate precipitations, and solid -phase adsorption to remove unwanted crossreactivity.
Form：Supplied as a liquid in 0.01M HEPES, pH 7.4, 0.15M sodium chloride and 50% glycerol. No preservative added.
Specificity：Recognizes human PF4. A single precipitin arc is observed with normal platelet lysate of identical mobility to that obtained with purified PF4. No reactivity was observed with plasma. Reacts with PF4-heparin complexes but does not inhibit PF4’s ability to neutralize heparin.
Isotype：IgG
Calc Applications Abbrev：E
Calc Crossreactivity：Hu
Immunogen：Platelet Factor 4 (PF4) purified from human platelet concentrate.
