生物化学fatty acid catabolism脂肪酸分解代谢

（脂肪酸分解代谢ZhangSchoolofLifeSciences&: :1Mobilizationoffats（TG）fromdietaryintakeandadiposetissuesfattyacidsKetone FAmetabolismregulationand23expendingabout25,000kJ/day(6,0003Lipids：insolubilityorlowersolubilityinHighlysolubleinnon-polar(非极性Theirwater-insolubilitycontributestomuchofthecomplexityintheirdigestion,transport,andmetabolism.* *polar,moreamphipathiclipidslipidCategories（Chemical--glyceride(甘油酯)wax（蜡5Biological--highmelting--energy--water-impermeable(不透水)棕榈 三十烷Triacontanyl-palmitateisthemajorcomponentofbeeswax. Naturaloilsmainlycontaintriacyl-glycerolswithunsaturatedfattyacids--liquidsatroomSolidfatscontainprimarilysaturatedfatty7--highmelting7--solidatroomCellMetab.2015Oct6;22(4):658-IntroductiontofattyacidsFatty yimportantBuildingblocksforphospholipids(磷脂&TargetproteinstoHighenergysourceofHormonesor9TwosourcesofFA:storedanddietaryFAsrepresenttheprincipalformofstoredenergyin)Thecarboninfattyacids(-CH2)iscomple yreduced-moreenergyFattyacidsarenothydrated,socanpackmorecloselyinstoragetissuesfattyacidpalmitic（16：0）、Palmitoleic（棕榈油酸)（16：1△9）、oleic（18：1△9Linoleic(亚油酸）（18：2△9，12）、α-linolenic（α-亚麻酸）（18：3△9，12，15）、γ-liolenic（γ-亚麻酸）（18：，14）EPA(20碳五烯酸）(20：5△5，8，11，14，17）DHA（22碳六烯酸）SaturatedVs.UnsaturatedPolarheadSaturatedFatty

FattyAcid1doubleStearicAcidC-硬脂

OleicAcidC-油 carbonnumberismostlythefirsttwinbondofmonounsaturatedFAismostlyinthe9thposition,andthesecond,thirdtwinbondaremostlyinthe12th,15thposition；mostdoublebondiscis,onlyfewistransTriglycerides甘油三酯，TG) Triglycerides(甘油三酯9kcal/gvs4kcal/gforBrownandwhiteActionofThermogenin（UCP1）inbrownfatcells tissuerepairandcellsStoredmetabolicfuelinaFatfromDiet&AdiposeAcquiredreadilyinthedietandcanalsobemadefromcarbohydratesandthecarbonskeletonsofaminoacidsTGsrepresentthemajorenergyinputinthedietofthemodernwesterncountriesandthecityareaofTGsarethemajorformofstoredenergyinthebodyinspecializedcells,adipocytesMobilizationoffatsfromdietaryintakeandadiposetissuesDegradationofdietaryoccursprimarilyintheMobilizationoffats：fatsEOther Inthestomach,asmallextentbylipasesinthelow-pHenvironmentIntheduodenum,alkalinepancreaticjuiceraisespH,allowinghydrolysisofTGbypancreaticlipaseandbynon-specifices PancreaticlipasereleasesfattyacidsfromtheC-1andC-3positionofTGOtherlipasesandnonspecifices sesattacktheC-2positionBilesaltsisafamilyofcarboxylicacidsaltswithsteroidbackbones,actingasdetergentstoemulsifyTGsandfacilitatetheactivityofthelipaseandes Pancreatic

PancreaticDegradationofdietaryPancreaticLipases(胰脂肪酶Absorption（吸收）andShortchainofFAsareabsorbeddirectlyintotheintestinalLongchainFAs(≥12C)combinewithbilesaltsinmixedmicelles，whichdeliverFAstoepithelialcellstoformnewTGs.NatRevGastroenterolHepatol.2015Apr;12(4):205-Absorption（吸收）andInintestinalmucosalcells(肠粘膜细胞),FAandmonoacylglyceridesareresynthesizedintoTGsandpackagedintochylomicrons(乳糜微粒).MovementofDietaryLipidfromSmallIntestinetoPeripheralTissues脂蛋白脂肪酶UtilizationofFattyAcidsasThreestagesofTriglycerolsaredegradedtofattyacidsandglycerolintheadiposetissue（脂肪组织）andtransportedtootherFattyacidsareactivatedandtransportedintotheFattyacidsarebrokendownintotwo-carbonCoAunitsandfedintothecitricacidBreakdownofIntheadiposetissue(脂肪组织lipasesareactivatedby Thefattyacidsaretransportredinthebloodbyserum Theglycerolisabsorbedbytheliverandconvertedtoglycolyticintermediates.ActivationofFattyAcids（活化AcylCoAsynthetasereactionoccursonthemitochondrialmembraneConsumptionof2脂酰辅酶ATransportintoactivatedfattyacidsintomitochondrialUssherJR,LopaschukGD,ArduiniA.GutmicrobiotametabolismofL-carnitineandcardiovascularrisk.Atherosclerosis,2013,231(2):456-461. FattyacidFranzKnoop’slabelingexperiments(1904)FAsaredegradedbyoxidationattheβcarbonatom.Acyl-1).oxidationtotrans-∆Acyl-（氧化反式烯酰2).HydrationtoL–3–HydroxylacylCoA（水合（烯酰CoA水合酶羟酰 Oxidationto（氧化L-Hydroxyacyl-CoA酮酰 Thiolysisto（硫解β-硫--16Cpalmitate（棕榈酸）produces106ATP's【Minusthe2fortheactivation(-2)】Migratorybirdstravellongdistancesonenergyfromfattyacidoxidation Somemigratorybirdsflywithoutstop andbuildbodyfatbefore–Thepercentageofdryweightbodyfatinthesebirdscanbeashigh70%whenmigrationbegins(vs~30%andlessfornon-migratoryFattyacidoxidationisanimportantsourceofmetabolicwaterforsomeanimalsSpecial 内容UnsaturatedfattyacidsUnsaturatedfattyacidsKetone ）,acetoacetate（乙酰乙酸）,and Theformationofketonebodies,synthesizedprimarilyinliverHMG-CoAHMG-CoA裂解乙酰乙乙酰乙酸脱羧 羟丁酸脱氢β-羟丁训练后2小 训练后12小乙酰乙酸 化FAmetabolismregulationandFAentersintomitochondriaInheart-inhibitbyacetyl-CoAandBodymetabolismneedLongtermdietchangefourreactionsremoveacetyl-CoAfromfattydehydrogenation(