| Formulation | 50%glycerol/water(v/v) |
| Storage | -20°C |
| Purity | >95%bySDS-PAGE |
| ActivityDetermination | N/A |
| ShelfLife(properlystored) | 12months |
Thedomainstructureofthethrombospondinmonomerisrepresented.Thethrombospondinmonomerisa150,000molecularweightglycopeptide.Regionscontainingaminoacidsequencehomologoustoprocollagen,properdinandepidermalgrowthfactor(EGF)areshown.Heparin,calciumion,andcellbindingdomainsareindicated.Nativethrombospondinisa450,000molecularweighthomotrimerconsistingofthreeidenticalpeptidechainslinkedthroughinterchaindisulfidebonds.
SampleGelInformation:
| Gel | Novex4-12%Bis-Tris |
|---|---|
| Load | Humanthrombospondin,1µgperlane |
| Buffer | MOPS |
| Standard | SeeBluePlus2;Myosin(191kDa),PhosphorylaseB(97kDa),BSA(64kDa),GlutamicDehydrogenase(51kDa),AlcoholDehydrogenase(39kDa),CarbonicAnhydrase(28kDa),MyoglobinRed(19kDa),Lysozyme(14kDa) |
Overview:
Thrombospondinisahigh-molecularweight,heparin-bindingglycoproteinconstituentofhumanplatelets(1).Rangingfrom30-50µgper109platelets,thrombospondinisoneofthemostabundantproteinsintheplateleta-granule(2,3).Thrombospondinwasinitiallytermed"thrombin-sensitiveprotein"baseduponitsreleasebythrombin-activatedplatelets(4,5).Structurally,thrombospondinisa450,000molecularweightglycoprotein(1)consistingofthree,identical,disulfide-linkedpolypeptidechains(6-8).Thebindingofthrombospondintothesurfaceofbothrestingandthrombin-activatedplateletshasbeenreported(9).Athrombospondin-specificmembranereceptorhasalsobeenpartiallycharacterized(10).Functionally,platelet-derivedthrombospondinmayplayaroleinplateletadherenceandaggregation(11).
Thrombospondinisnotanexclusiveproductofplateletsandmegakaryoctes.Thesynthesisofthrombospondinbyendothelialcells(12),fibroblasts(13),monocytesandmacrophages(14),andosteoblasts(15)hasbeenreported.Thrombospondinisalsoanintegralcomponentofthebasementmembraneinanumberofdifferenttissues(16).Thrombospondininteractswithavarietyofextracellularmacromoleculesincludingheparin(1,17),collagen(18),fibrinogenandfibronectin(19),plasminogen(20),plasminogenactivator(21),andosteonectin(22).ThroughthecollectiveeffortsofanumberofdifferentinvestigatorsemployingbothpeptidechemistryandCDNAanalyticaltechniques,distinctheparin,Ca2+-ion,platelet,andproteinbindingdomainswithinthrombospondinhavebeenidentified(23).Baseduponitsspecificinteractionswithbothcellsandextracellularmatrixcomponents,thrombospondinhasbeenhypothesizedtobeamemberofaclassofextracellularproteinswhichmaymodulatecell-matrixinteractions(24).
Ourhumanthrombospondin(TSP-1)ispreparedfromthesupernatantofactivatedplateletsbyheparin-agaroseaffinityandgelfiltrationchromatography(25).Thepurifiedproteinissuppliedin50%vol/volglycerol/H2Oandshouldbestoredat-20°C.PurityisassessedbySDS-PAGEanalysis.
Properties:
| Localization | plateletalpha-granule,extracellularmatrix | |||||
|---|---|---|---|---|---|---|
| ModeofAction | plateletadherence/aggregation,cell-matrixinteractions | |||||
| Molecularweight | 450,000(1) | |||||
| Extinctioncoefficient |
| |||||
| Isoelectricpoint | 4.7(1) | |||||
| Structure | Homotrimer(monomer,Mr~150,000)(6-8) | |||||
| PercentCarbohydrate | 4%(1) |
