Lipidmetabolism脂类代谢

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1、10.LipidmetabolismHuangxiaoLinyiuniversityKeynotesStructuresandrolesoffattyacidsFattyacidbreakdownFattyacidsynthesisTriacylglycerols10.1StructuresandrolesoffattyacidsFattyacidshavealonghydrocarbonchainwithaterminalcarboxylicacidgroup.Mostfattyacidshaveanevennum

2、berofcarbonatomsinanunbranchedchain.Saturatedfattyacidshavenodoublebondsbetweenthecarbonatoms,whereasmono-andpolyunsaturatedfattyacidshaveoneormoredoublebonds.Stearicacid(b)Fattyacidshavefourmajorbiologicalroles:1)Theyarecomponentsofmembranes(glycerophospholipi

3、dsandsphingolipids)2)Severalproteinsarecovalentlymodifiedbyfattyacids.3)Theyactasenergystores(triacylglycerols)andfuelmolecules.4)Fattyacidderivativesserveashormonesandintracellularsecondmessengers.10.2FattyacidbreakdownOverviewActivationTransportintomitochondr

4、iaβ-oxidationpathwayEnergyyieldKetonebodies1.overviewFattyacidbreakdownbringsabouttheoxidationoflong-chainfattyacids.ThefattyacidsarefirstconvertedtotheiracylcoenzymeAderivativesandthendegradedbythesuccessiveremovaloftwo-carbonunitsfromtheendofthefattyacidasace

5、tylCoA.IncytosolAcylCoAsynthetase2.FattyacidactivationRCOOH+CoA—SHRCO~SCoAAcylCoAsynthetaseATPAMP+PPiMg2+H2O2PithereactionisirreversiblefattyacidacylCoA3.TransportintomitochondrialongerchainacylCoAsdonotreadilycrosstheinnermitochondrialmembrane,andrequireaspeci

6、fictransportmechanism.RCO-SCoACoA-SHtransferase(CH3)3N+-CH2CH-CH2COOHOHcarnitine(CH3)3N+CH2CHCH2COOHRCO-OacylcarnitineR-COSCoAH-SCoAcarnitineR-CO-carnitineR-CO-carnitineH-SCoAcarnitineR-COSCoAtransferaseⅠβ-oxidationtransferaseⅡInnermitochondrialmembrane4.β-Oxid

7、ationpathwayOxidation(byFAD)HydrationOxidation(byNAD+)Thiolysis①oxidationacylCoAdehydrogenaseFADFADH2②hydrationRCH2CCCO~CoAHHtrans2-enoylCoAenoylCoAhydrataseH2OOHRCH2CHCH2CO~SCoA3-hydroxyacylCoA1.5ATPrespiratorychainＯR-CH2-CH2C-SCoA

8、

9、OHRCH2CHCH2CO~SCoA③oxidati

10、onNAD+NADH+H+dehydrogenase④thiolysisCH3CO~SCoARCH2CO~SCoA（1）（2）（3）（4）3-ketoacylCoARCH2C~SCoAOCH2COCoA-SHketothiolase2.5ATPrespiratorychainroundreactionOxidationofodd-chainfa