Formulation50%glycerol/water(v/v)Storage-20°CPurity>95%bySDS-PAGEActivityDeterminationN/AShelfLife(properlystored)12monthsDomainStructureofProteinZThedomainstructureofproteinZisrepresented,whereGLA=theregioncontainingγ-carboxyglutamicacidresidues;EGF=theregioncontainingsequenceshomologoustohumanepidermalgrowthfactor;pseudocatalyticdomain=regionhomologoustothecatalyticchainofserineproteaseswhichlackstheactivesiteHisandSerresiduesnormallyconservedinthecatalytictriad.SampleGelInformation:LoadHumanProteinZ,1µgperlaneBufferMOPSStandardSeeBluePlus2;Myosin(191kDa),PhosphorylaseB(97kDa),BSA(64kDa),GlutamicDehydrogenase(51kDa),AlcoholDehydrogenase(39kDa),CarbonicAnhydrase(28kDa),MyoglobinRed(19kDa),Lysozyme(14kDa)Overview:HumanproteinZ(PZ)isasinglechain,vitaminK-dependantplasmaprotein(1,2).Analogouswiththemajorityofthecoagulationproteins,proteinZissynthesizedintheliver.Thematureproteincontains360aminoacids(4).BasedonaminoacidsequencehomologythedomainstructureissimilartothatofothervitaminK-dependantzymogenswhichinclude;factorVII,factorIX,factorX,andproteinC(3,4).TheN-terminalregioncontainsacarboxyglutamicacid(Gla)domainimportantinitsphospholipidmembranebindingABIlity(5).FollowingtheN-terminalGladomainaretwoEGFdomainsandaregionwhichconnectstoacatalytic-likedomain(3,4).TheC-terminalregionhasbeenshowntolackthe"typical"serineproteaseactivationsiteaswellastheHisandSerresiduesfromthecatalytictriad(3,4).Proteaseactivityhasnotbeendetectedineitherthefull-lengthproteinorcleavageproductsofproteinZ(2).FunctionallyproteinZhasbeenshowntobeadirectrequirementforthebindingofthrombintoendothelialphospholipids(6,7).ProteinZalsoservesasacofactorfortheinhibitionofcoagulationfactorXabyaplasmaserpincalledproteinZ-dependantproteaseinhibitor(ZPI)(8).InhibitionisdependantuponcomplexformationbetweenfactorXa-PZ-ZPIonthephospholipidsurface(8).ThephysiologicalfunctionofproteinZisstillratherilldefined.Asisthecasewithothercoagulationproteinsandinhibitors,proteinZisconsumedduringdisseminatedintravascularcoagulation(DIC)(9).FurThermore,patientsdiagnosedwithaproteinZdeficiencypresentwithabnormalbleedingdiathesisduringandaftersurgicalevents(10).ThesefindingsprovidedirectevidenceastotheimportanceofproteinZinbloodcoagulation.HumanproteinZispreparedfromfreshfrozenplasmasimilartotheproceduredescribedbyBrozeandMiletich(2).ThepurifiedproteinZissuppliedin50%(vol/vol)glycerol/H2Oandshouldbestoredat-20oC.PurityisassessedbySDS-PAGEanalysis.Properties:LocalizationPlasmaPlasmaconcentration2.7µg/ml(11)ModeofactionRequiredforthebindingofthrombintophospholipidsurfacesandforPZdependantinhibitionoffactorXa.Molecularweight62,000(2)ExtinctioncoefficientE1%1cm,280nm=12.0(2)StructureSinglechain,(Mr=62,000),displaysstructuralsimilaritytoothervitaminK-dependantcoagulationfactorsbasedonsequencehomology,mostnotablyfactorX(3,4)