Platelet factor 4 (PF4/CXCL4) is an ELR− tetrameric, cationic chemokine that constitutes 25% of the protein in platelet α-granules. It is also found bound to the luminal vascular endothelial surface. Although platelets represent the primary source of PF4, it is also expressed at lower levels in other cells of the immune system including cultured T cells, monocytes, and endothelial and smooth muscle cells.
Alternative Names
C-X-C motif chemokine 4 ; PF-4
Quantity
20 µg
Regulatory
RUO
Source
E. coli
Host
Mouse
Endotoxin Level
<1.0 EU/μg of recombinant protein as determined by the LAL method.
Biological Activity Comment
Determined by its ability to inhibit human FGF-basic-dependent proliferation of NR6R-3T3 mouse fibroblasts. The ED50 for this effect is typically 5.0-15 μg/mL.
Weight
9.0 kDa
Description
A quick spin of the vial followed by reconstitution in distilled water to a concentration not less than 0.1 mg/mL. This solution can then be diluted into other buffers.
Format
Lyophilized PowderLyophilized from a 0.2 μm filtered solution in PB and 1.5M NaCl pH 7.4.
Purity
>95% as determined by SDS-PAGE
Storage
The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at 2° - 8°C for one month, or at -20°C for six months, with a carrier protein without detectable loss of activity. Avoid repeated freeze/thaw cycles.