Formulation50%glycerol/500uMEDTA(v/v)Storage-20°CPurity>95%bySDS-PAGEActivityDeterminationPhotometricdeterminationShelfLife(properlystored)12monthsStABIlizationofFibrinTheconversionofsolublefibrintoaninsolublefibrinclotiscatalyzedbythetransamidasefactorXIIIa.Lysineandglutaminesidechainsofα-andγ-chainsoffibrinarecrosslinkedtoformhomopolymers.SampleGelInformation:GelNovex4-12%Bis-TrisLoadHumanFactorXIIIa,1µgperlaneBufferMOPSStandardSeeBluePlus2;Myosin(191kDa),PhosphorylaseB(97kDa),BSA(64kDa),GlutamicDehydrogenase(51kDa),AlcoholDehydrogenase(39kDa),CarbonicAnhydrase(28kDa),MyoglobinRed(19kDa),Lysozyme(14kDa)SpecialNotesInthenon-reducedsampletheAchainshiftsdowntowardtheBchainfollowingactivation.Overview:FactorXIIIa(FXIIIa)(fibrinoligase,plasmatransglutaminase,fibrinstabilizingfactor,E.C.2.3.2.13)isaglutaminyl-peptideγ-glutamyltransferasefunctioninginthefinalstagesofthecoagulationcascade,stabilizingthefibrinclotbycrosslinkingtheαandγchainsoffibrintoformhomopolymers(1-4).SeveraluniquefeaturesofFXIIIasetitapartfromproteinswithwhichitisgenerallyassociated.FactorXIIIaistheonlynon-proteolyticenzymeofthecoagulationcascade.Unlikeothertransamidases,itexiststotallyinzymogenicformandistheonlysulfhydrylaseenzymewhichfunctionsextracellularly.PlasmaFXIIIaisatetramer,(Mr=312,000),composedof2pairsofnon-identicalsubunits(A2B2)(4-7).PlateletFXIIIisadimer(Mr=46,000),composedofonlyapairofidenticalAsubunits(A2)asisfactorXIIIfromallintracellularsources(7-11).TheAsubunitcontains6freesulfhydrylgroups,oneofwhichistheactivecenter(12).TheconversionofplasmaFXIII(A2B2)totheactivetransglutaminase,FXIIIa(A2")resultsfromthethrombincatalyzedhydrolysisoftheArg36-Gly37peptidebondattheNH2-terminaloftheAsubunit(13).Theconformationalchangeinducedbythiscleavageresultsinexposureoftheactivesitecysteine.FullactivityisachievedonlyaftertheCa2+dependent(Kd=10-3M)dissociationoftheBsubunitdimerfromtheA2"dimer(14-16).DissociationoftheA2"B2complexisenhancedbybindingtotheregionoffibrin(ogen)containingresidues242-424oftheAachain(14-16).Thus,atnormalplasmaconcentrationsofFXIII(90nM),fibrinogen(8µM)andCa2+(2.5mMfree),alltheFXIIIageneratedwouldbeinthefullyactivated(A2")molecularform.OtherphysiologicallyrelevantcrosslinkedcomplexesgeneratedbyFXIIIaincludefibrin-fibrinogen(17),fibrin-fibronectin(18),fibrin-vWF(19),fibrin-α2-antiplasmin(20),fibrin-actin(21),fibrin-thrombospondin,fibronectin-collagen(19),vWF-collagen(19),actin-myosin(21,22),factorV-factorV(23).Inadditiontoclotstabilization,FXIIIaisthoughttofunctioninvariousprocessesinvolvingcellproliferation,suchaswoundhealing,tissueremodeling,atherosclerosis,andtumorgrowth.PlasmaFXIIIaisgeneratedbycleavageofhomogenousplasmaFXIIIbyalpha-thrombin,inthepresenceofEDTA.TheA2"B2subunitispurifiedbyionandaffinitychromatographyandsuppliedin50%glycerol,0.5mMEDTAforstorageat-20°C.Properties:LocalizationPlasmaModeofactionPlasmatransglutaminaseMolecularweight312,000(4)ExtinctioncoefficientE1%1cm,280nm=13.8(4)-(inferredfromthezymogen,factorXIII)Isoelectricpoint5.2(inferredfromthezymogen,factorXIII)Structuretetramer(A2"B2)intheabsenceofcalcium,twoidenticalAchains(Mr=71,000)eachcontaining6freesulfhydrylsandandactivesite,twoidenticalBsubunit(Mr=88,000)identicalsubunits,A(Mr=75,000),B(Mr=88,000)/td>CarbohydrateContentAchain:1%Bchain:5%