Alpha-thrombinisaserineproteaseandakeyenzymeinthebloodcoagulation
woundhealingprocesses.Thrombinisgeneratedbyproteolyticactivationofthe
zymogenprothrombinandiscommonlyrecognizedastheenzymeresponsIBLefo
theconversionoffibrinogentofibrin.Inadditiontocleavingfibrinogen,thrombin
isresponsibleforactivatingplateletsandisindirectlyresponsibleforregulation
itsownproductionandinhibitionthroughmultipleproteolyticfeedbackpathway
whichincludetheactivationoffactorsV,VIII,XIandProteinC.Thecentral
importanceofthrombintotheoverallcoagulationprocessisestablishedbythe
factthatanyperturbationwithinthebloodcoagulationsystemthatresultsin
significantlyamplifiedorimpairedaswellasacceleratedordelayedthrombin
generationwillresultinclinicallyrelevanthemorrhagicorthromboticevents.
Thrombinactivityisdown-regulatedbyinactivationofthecofactors,factorVaa
VIIIaorbydirectinhibitionofthrombinbyitsprincipalinhibitor,anti-thrombin-III
Inadditiontoitspivitolroleinthebloodcoagulationprocess,thrombinalso
contributestothewoundhealingprocess.Itactivatesproteaseactivated
receptor-1(PAR-1)andinthismannercanaffectcellularfunction,growthand
proliferation.Intactthrombin,aswellasfragmentsofthrombin,havealsobeen
showntohaveangiogenic,mitogenicandchemotacticactivities.