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《3-Hydroxyisobutyrate Dehydrogenase Is Involved in3-羟基异丁酸脱氢酶参与 Valine和异亮氨酸的降解 拟南芥TaLaNa1》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、3-HydroxyisobutyrateDehydrogenaseIsInvolvedinBoth,ValineandIsoleucineDegradationin1[OPEN]Arabidopsisthaliana2PeterSchertl,LennartDanne,andHans-PeterBraunInstitutfürPflanzengenetik,LeibnizUniversitätHannover,30419Hannover,GermanyORCIDID:0000-0002-4459-9727(H.-P.B.).Inplants,ami
2、noacidcatabolismisespeciallyrelevantinmetabolicstresssituations(e.g.limitedcarbohydrateavailabilityduringextendeddarkness).Undertheseconditions,aminoacidsareusedasalternativesubstratesforrespiration.Completeoxidationofthebranched-chainaminoacids(BCAAs)leucine,isoleucine(Ile),
3、andvaline(Val)inthemitochondriaefficientlyallowstheformationofATPbyoxidativephosphorylation.However,themetabolicpathwaysforBCAAbreakdownarelargelyunknownsofarinplants.AsystematicsearchforArabidopsis(Arabidopsisthaliana)genesencodingproteinsresemblingenzymesinvolvedinBCAAcatabo
4、lisminanimals,fungi,andbacteriaaswellasproteomicanalysesofmitochondrialfractionsfromArabidopsisallowedtheidentificationofaputative3-hydroxyisobutyratedehydrogenase,AtHDH1(At4g20930),involvedinValdegradation.Systematicsubstratescreeninganalysesrevealedthattheproteinuses3-hydrox
5、yisobutyratebutadditionally3-hydroxypropionateassubstrates.ThispointstoaroleoftheenzymenotonlyinValbutpossiblyalsoinIlemetabolism.At4g20930knockdownplantswerecharacterizedtotestthisconclusion.Roottoxicityassaysrevealedincreasedrootgrowthinhibitionofthemutantsifcultivatedinthe
6、presenceofValorIlebutnotinthepresenceofleucine.WeconcludethatAtHDH1hasadualroleinBCAAmetabolisminplants.Plantscansynthesizeall20proteinogenicaminoforrespirationinlow-lightconditionsorextendedacids.Theircarbonskeletonsandaminogroupsdi-darkness.Uponlightshortage,theavailability
7、ofcar-rectlyorindirectlyderivefromphotosynthesis.Besidesbohydratesforrespirationislimited,andaminoacidsaminoacidbiosynthesis,plantsalsocanbreakdownallcanbeusedasalternativerespiratorysubstrates(Araújo20aminoacids.Aminoacidcatabolismisespeciallyetal.,2011).Aminoacidcatabolismm
8、ainlytakesplaceinrelevantinthecontextofgermination(theconversionofth
