| Formulation | 50%glycerol/water(v/v) |
| Storage | -20°C |
| Purity | >95%bySDS-PAGE |
| ActivityDetermination | FactorXIclottingassay |
| ShelfLife(properlystored) | 12months |
TheactivationoffactorXIbyfactorXIIaisillustrated.AlthoughfactorXIcanbindindependentlytonegativelychargedsurfaces,proteolysisbyfactorXIIacanonlyoccurinthepresenceofsurface-boundhighmolecularweightkininogen(HMWKa).TheboundHMWKaissusceptIBLetoproteolysisbythenewlygeneratedfactorXIawhichresultsinalossofitsBIOLOGicalactivity(HMWKi).FactorXIacatalyzestheproteolyticconversionoffactorIXtofactorIXaeitherinsolutionphaseorwhenboundtoanegativelychargedsurface.
SampleGelInformation:
| Gel | Novex4-12%Bis-Tris |
|---|---|
| Load | HumanFactorXIa,1µgperlane |
| Buffer | MOPS |
| Standard | SeeBluePlus2;Myosin(191kDa),PhosphorylaseB(97kDa),BSA(64kDa),GlutamicDehydrogenase(51kDa),AlcoholDehydrogenase(39kDa),CarbonicAnhydrase(28kDa),MyoglobinRed(19kDa),Lysozyme(14kDa) |
Overview:
ProteolysisofXIbyfactorXIIainthepresenceofhighmolecularweightkininogen(HMWK),yieldstheenzymefactorXIa(1-3).FactorXIaisaserineproteasewhichparticipatesintheintrinsicpathwayofcoagulationbycatalyzingtheconversionoffactorIXtofactorIXa.BecausefactorXIisahomodimer,theenzyme,factorXIa,iscomposedoftwoidenticalheavychains(Mr=50,000),andtwoidenticallightchains(Mr=30,000),allofwhichareheldtogetherbydisulfidebonds.ThislatterpropertymakesfactorXIauniqueamongtheserineproteases,sinceitcontainstwoactivesitespermolecule(1-3).
FactorXIa,likeitsprecursorfactorXI,remainsincomplexwithHMWK(4).Incomplexform,factorXIa/HMWKiscapableofactivatingfactorXIItofactorXIIaandprekallikreintokallikrein.Additionally,inthecomplexedform,factorXIaislessaffectedbyproteaseinhibitors(5).ThemajorplasmainhibitoroffactorXIaisa1-antitrypsinandthentoamuchlesserextent,antithrombin-III(5,6).Whileinthecomplexedform,factorXIamaycatalyzetheproteolysisofHMWK,yieldingabiologicallyinactiveformofHMWK(HMWKi),thusallowingdissociationoftheFactorXIa/HMWKicomplex.EitherfreefactorXIaorthefactorXIa/HMWKcomplexcatalyzestheproteolyticconversionoffactorIXtofactorIXa.
FactorXIaispreparedbyactivatingpurifiedfactorXIwithfactorXIIa.Followingactivation,themixtureispassedoveracolumnofimmobilizedanti-factorXIItoremovethefactorXIIa,andfurtherpurifiedonheparin-Sepharose.ThefactorXIaissuppliedin50%(vol/vol)glycerol/H2Oandshouldbestoredat-20°C.PurityisassessedbySDSPAGEanalysis.ActivityisdeterminedinaclottingassayusingfactorXIdeficientplasma.
Properties:
| Localization | Plasma;inassociationwithhighmolecularweightkininogen | |||||
|---|---|---|---|---|---|---|
| Modeofaction | AserineproteasethatconvertsfactorIXtofactorIXa | |||||
| Molecularweight | 160,000(1,2) | |||||
| Extinctioncoefficient |
| |||||
| Structure | twoapparentlyidenticalheavychains(Mr~50,000)andtwoapparentlyidenticallightchains(Mr~30,000)heldtogetherbydisulfidebonds.Eachlightchaincontainsacatalyticdomain(1,3). | |||||
| Percentcarbohydrate | 5%(human)(1) |
