《厦大生化》PPT课件

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1、Chapter26ThebiosynthesisofmembranelipidsandsteroidsFatssuchasthetriacylglycerolmoleculearewildlyusedtostoreexcessenergyforlateruseandtofulfillotherpurposes.26.1PhosphatidateisacommonintermediateinthesynthesisofphospholipidsandtriacylglycerolsGlycerolphosphateacyltransferase.Endoplasmicreticu

2、lum/Outermitochondrialmembrane.Diglycerideacyltransferase.Triacylglcerolsynthetasecomplexinliver.26.1.1ThesynthesisofphospholipidsrequiresanactivatedintermediatePhospholipidsynthesis=thecombinationofadiacylglyceridewithanalcoholAnabolicreactionDiacylglyceroloralcoholshouldbeactivated.Synthes

3、isfromanactivateddiacylglerolStructureofCDP-diacylglycerol.SynthesisformanactivatedalcoholInallofbiosyntheses,anactivatedintermediate(UDP-glucose,CDP-diacylglycerol,CDP-alcohol)isformedfromaphosphorylatedsubstrate(glucose-1-phosphate,phosphatide,phosphorylalcohol)andanucleosidetriphosphate.T

4、heactivatedintermediatethenreactswithahydroxylgroup(theterminusofglycogen,thesidechainofserine,oradiacylglycerol).26.1.2PlasmalogensandotheretherphospholipidsaresynthesizedfromdihydroxyacetonephosphateSynthesisofanetherphospholipid.26.1.3Sphingolipidsaresynthesizedfromceramide鞘氨醇Synthesisofs

5、phingolipids.神经酰胺葡萄糖脑苷脂神经节苷脂鞘磷脂GangliosideGM1.半乳糖唾液酸N-乙酰半乳糖胺葡萄糖26.1.4RespiratorydistresssyndromeandTay-SachsdiseaseresultfromthedisruptionoflipidmetabolismTay-Sachsdisease（泰萨氏幼年黑朦白痴症）(1)A1-year-oldinfantwithTay-Sachsdisease.(2)Electronmicrographofaportionofanaffectedbraincell,showingtheabnor

6、malgangliosidedepositsinthelysosomes.26.2CholesterolissynthesizedfromacetylcoenzymeAinthreestagesLabelingofcholesterol.26.2.1Thesynthesisofmevalonate,whichisactivatedasisopentenylpyrophosphate,initiatesthesynthesisofcholesterolFatesof3-hydroxy-3-methylglutarylCoA.二羟甲基戊酸Synthesisofisopentenyl

7、pyrophosphate.Squalenesynthesis.异戊二烯基转移酶焦磷酸牻牛儿酯26.2.2SqualenecyclizestoformcholesterolSqualenecyclization.Oxidosqualenecyclase.Cholesterolformation.26.3ThecomplexregulationofcholesterolbiosynthesistakesplaceatseverallevelsHMG-CoAreductase.3-hydroxy