HtrA4isasecretedhumanserineproteaseissupposedtoformoligomersofidenticalproteinchainsasrevealedbyX-rayanalysisforthebacterialHtrAproteinDegP[1].PolypeptidechainsofhumanHtrA4consistofseveraldomains:AnN-terminalinsulin-likegrowthfactordomainisfollowedbyaKazal-typeserineproteaseinhibitordomain,alinkerregion,atrypsin-likeproteasedomainandaPDZdomain[2].ThefunctionofHtrA4isaprobableserineprotease. Noinformationisavailableyetonphysiologicalsubstratesorinteractingproteins.

Purity:RecombinantHtrA4appearsasamajorproteinofabout50kDainSDS-PAGE(>70%oftotalprotein).

EnzymaticActivity:ProteolyticactivityofrecombinanthumanHtrA4isdocumentedbydigestionofß-casein. 0.5mgß-casein/mlarecompletelydigestedby10μg/mlHtrA4within18hoursat37°C(seePDfinsert).

StABIlity&Storage:RecombinanthumanHtrA4isstableuntiltheexpirydategivenonthelabelwhenstoredat-70°C.Repeatedfreezingandthawingshouldbeavoided.

Applications:RecombinantHtrA4allowdetailedstudiesofthestructureandfunctionofthisprotease.Theenzymeisusedtoscreenforinhibitorsandtocharacterizeinhibitoractions.RecombinantHtrA4canalsoserveasstandardinenzymaticandimmunochemicalassays.