Studies on the mechanisms of histidase development in rat skin and liver: I. Basis for tissue specific developmental changes in catalytic activity☆

[摘要] Skinandliverhistidasesoftheratfollowmarkedlydifferingdevelopmentalcourses.Inskin,theenzymeactivityemergesinlatefetallife,risestoamaximumduringthefirstpostnatalweekandthendeclines;inliver,histidaseactivityinitiallyappearsintheneonatalperiodandprogressivelyrisesthereafter.Theenzymesinbothtissues,however,areimmunologicallyidentical,asdemonstratedbyOuchterlonydoublediffusion,immunoelectrophoresis,andimmunotitrationanalysesofhistidaseinadultanimals.Furthermore,althoughcrudepreparationsofskinandliverhistidasedifferslightlyinelectrophoreticmobilityonacrylamidegels,theisoelectricpointsandMichaelisconstantsoftheenzymefrombothskinandliverarethesame.Duringdevelopmentneitherdissociableactivatorsnorinhibitorsoftheenzymeareevident,whichmightaccountforthedivergentdevelopmentalpatterns,norareenzymeinhibitorsfoundintissuesdevoidofhistidaseactivity.Noimmunologicallycross-reactingmaterialsaredetectableinskinandliveratdevelopmentalstagespriortotheemergenceofenzymeactivity,norintissuesnotexpressinghistidasecatalyticactivity.Furthermore,thereisnoevidenceofelaborationofimmunologicalvariantsofhistidaseinskinandliverduringdevelopment.Thesedataarecompatiblewiththeviewthatalldevelopmentalchangesincatalyticactivityareduetoalteredamountsofthesameenzymeantigen.

[学科分类] 生物科学（综合）