《生物化学》学习提纲细化版

PAGEPAGE11《生物化学》复习提纲1.AnoverviewofmetabolismUniversalcarriersofelectrons，functioninreactions——NAD+/NADH,NDAP+/NADPH,FAD/FADH2NAD+,NADP+,FADarethefewcommonlyusedsuchreversibleelectroncarriers.NADandNADParedinucleotidesabletoaccept/donateahydrideion(thuswith2e-)foreachroundofreduction/oxidation.ReductionofNAD+andNADP+canbeeasilyfollowedbyspectroscopy(at340nm).IneachspecificNAD-orNADP-containingdehydrogenase,thehydrideionisadded/takenstereospecificallyfromoneside(AorB)ofthenicotinamide(烟碱)ring.FADisabletoaccept/donateoneortwoelectrons(ashydrogenatom),withabsorptionmaximumshiftsfrom570nmto450nm.NADandNADPcaneasilydiffuseoutoftheenzymes,butFMNandFADaretightlyboundtotheenzymes.NADHandFADH2willbefurtheroxidizedviatherespiratorychainontheinnermembraneofmitochondriaorplasmamembraneofbacteriaforenergygeneration(transduction).CalculateG（>0,<0,=0）ΔG＝ΔG0－RTln[B]/[A]G=G‘o+RTlnQG'o=-RTlnK'eq2.OxidativePhosphorylationDefinition/Respiratorychain;Fourcomplexes,ComplexI:NADH-Qoxidoreductase：NADH+Q+2H+→NAD++QH2+4H+ComplexII:Succinate-Qreductase：FADH2+Q+2H+→FAD+QH2ComplexIII:Q-cytochromecoxidoreductase：QH2+2H++2Cytc（oxidized）→Q+4H++2Cytc(reduced)ComplexIV:Cytochromecoxidase：4Cytc(reduced)+8H+N+O2→4Cytc(oxidized)+4H+P+2H2OProtonpumpsandeachfunctions;aprotongrandientpowersthesynthesisofATP;Qcyclepeocess;ThespecialcharacteristicsofQ：Doubleelectron-carrier、Lipidsoluble、AcrossmembraneThechemiosmoticmodelofMitchellanditsdefinitionTheacross-membraneprotongradientwasthusfinallyacceptedasthedrivingforceforATPsynthesis:thechemiosmotic(化学渗透)modelwasacceptedasatheory.TheATPsynthase;Fo/F1;structureandfunction,howATPisproducedviaATPsynthase;TheATPsynthasecomprisesaprotonchannel(Fo)andaATPase(F1)。TheFoportionconsiststhreetypesofsubunits:ab2c10-12。TheF1partconsistsofninesubunitsoffivetypes:a3b3γδε。NADHandFADH2shuttlemovementswillgenerateATPmolecules.1NADH→10protons→2.5ATP1FADH2→6protons→1.5ATP3.TheLightReactionofPhotosynthesisElectrontransportthroughPSIandPSII;Cyclicandnon-cyclicpathways.Cyclicelectronflow:Thesimpler,involvingonlyphotosystemIandgeneratesonlyATP。Noncyclic:usesbothsystems,generatesATPandNADPHandoxygenisreleased.KeyenzymeinCalvinCycle.Rubisco二磷酸核酮糖羧化酶4.GlycolysisandGluconeoganesisGlycolysis:keyenzymes,reactionsteps;substrate-levelphosphorylation;ATPandNADHHexokinase(己糖激酶)、Phosphofructokinase-1(PFK-1,磷酸果糖激酶-1)、Thepyruvatekinase（丙酮酸激酶）。1moleculeglucosewasdecomposedinto2moleculespyruvate，2moleculesofATP，and2moleculesofNADH+H+。CoricycleCoricycleandAlaine-GlucosecycleCoricycleGluconeogenesis2Pyruvate+4ATP+2GTP+2NADH+4H2O→glucose+4ADP+2GDP+6Pi+2NAD++2H+Glycolysis：Glucose+2ADP+2Pi+2NAD+→2Pyruvate+2ATP+2NADH+2H++2H2OGlucogenicaminoacidAla,Cys,Gly,Ser,Thr,Trp→pyruvatePro，His，Gln，Arg→Glu→α-ketoglutaricacidIle，Met，Ser，Thr，Val→succinyl-CoAPhe，Tyr→fumarateAsn，Asp→oxaloaceticacidGlycerinephosphodihydroxyacetoneLacticacidpyruvate5.GlycogenMetabolismGlyconeogenesis/glycolysis————differencesofreactionsteps,3reversereactionsThemajorprecursorsforgluconeogenesis：Lactate,pyruvate,glycerol,and3-phosphoglycerate,catalyzingenzymes;Glycogenolysis/glycogensynthesis——activatedglucose:UDP-glucosePhosphorylase(R/T),Regulationofglycogenmetabolism;(fordifferentenzymes)Step1:hydrolyse：(G)n→(G)n-1+G-1-PStep2:Isomerism：G-1-P→G-6-P（catalyzedbyphosphoglucomutase）Step3:dephosphorylation：Glucose-6-phosphate+H2O→glucose+PiAllenzymeswithPLPascoenzyme;pyridoxalphosphate(PLP)AdebranchingenzymealsoisneededforthebreakdownofglycogenPhosphoglucomutasecovertsG-1-PintoG-6-phosphateAhydrolyticenzymeorG-6-Phosphatase(inliver)5.TheCitricAcidCycleImportantintermediates,8steps;Keyenzymes:NADH/FADH2Acetyl-CoA+3NAD++FAD+GDP+Pi+2H2O→2CO2+3NADH+FADH2+GTP+2H++CoA关键酶：PyruvatedehydrogenasecomplexCitratesynthaseIsocitratedehydrogenasea-ketoglutaratedehydrogenasepyruvatedehydrogenasecomplexandreaction;丙酮酸脱氢酶复合物E1pyruvatedehydrogenase丙酮酸脱氢酶E2dihydrolipoyltransacetylase二氢硫辛酸转乙酰酶E3dihydrolipoyldehydrogenase二氢硫辛酸脱氢酶6cofactorTPP[thiaminepyrophosphate]焦磷酸硫胺素，lipoicin(硫辛酸)，NAD+，FAD，HSCoA,Mg2+NADHandFADH2transmembrane;Pentosephosphatepathway,allintermediateG-6-P+12NADP++7H2O→6CO2+12NADPH+12H++H3PO4Incytoplasmintermediateproducts:D-ribulose5-PandNADPHKeyenzyme:glucose-6-phosphatedehydrogenaseFunctionofPPP;products:D-ribulose5-PandNADPH;Keyenzyme:glucose-6-phosphatedehydrogenasethesignificanceofPentosephosphatepathway：Toprovidethe5-phosphateribuloseforsynthesisofnucleinicacidandribonucleotidecoezymes(NAD)ReparationandregenerationToprovideNADPHforsomemetablicreactions7.FattyAcidMetabolismDegradation－oxidativepathway:oxidationbyFAD,hydration,oxidationbyNAD+,thiolysisbyCoATakingplace;stepsandenzymes;ATPsynthesis,C2n/C2n+1Carnitine;keyratereaction;CoenzymeB12Ketonebodies:acetoacetate,-hydroxylbutyrate,andacetone答：Step1Fattyacid’sactivation：Fattyacidsareconvertedtofattyacyl-CoA(ahighenergycompound)viaafatty-acyl-adenylateintermediatebytheactionoffattyacyl-CoAsynthetases(alsocalledfattyacidthiokinase).Pyrophosphateishydrolyzedbyinorganicpyrophosphatase。Step2ActivatedfattyacidsarecarriedintothematrixbyCarnitine。Step3Fattyacyl-CoAisoxidizedtoacetyl-CoAviamultipleroundsofboxidation。oxidation：Palmitol-CoA+7CoA+7FAD+7NAD++7H2O→8acetyl-CoA+7FADH2+7NADH+7H+Thecompleteoxidizationofeach16-carbonpalmitate(toH2OandCO2)yields~106ATP(~32ATPperglucose,bothhavingabout60%ofactualenergyrecovery).C2n：nCH3CO~SCOA,n-1-oxidationC2n+1：n-1CH3CO~SCOA,1PropionylCOA，n-1-oxidationSynthesis7proteincomplexes,andeachfunction;Sulfhydrylgroupcarriers:ACP/CoAReductant:NADPH/NADH/FADH2Atotalof7ATPand14NADPHwillbeconsumedformakingonepalmitatemolecule.8acetyl-CoA+7ATP+14NAPDH+14H+→palmitate+8CoA+6H2O+7ADP+7Pi+14NADP+8.ProteinTurnoverandAminoacidCatabolismAminotransferase:PLPDifferentaminotransferases(e.g.,aspartateandalanineaminotransferases),eachcatalyzesthetransferoftheaminogroupfromanaminoacidtoa-ketoglutaratetoformGluandaa-ketoacidPLP(Pyridoxalphosphate)磷酸吡哆醛Alanine-glucosecycleUreacycle,stepsandenzymes;ThemoleculesofN/C:NH3,CO2andAsp;Step1:acarbamoylphosphateisproduced，carbamoylphosphatesynthetaseIStep2：citrullineproduction，ornithinetranscarbamoylaseStep3：argininosuccinateisproduced，ArgininosuccinatesynthaseStep4：TheargininosuccinateisthencleavedtoformArgandfumarate,inareactioncatalyzedbyargininosuccinatelyase.Step5：ureaproductionandregenerationofornithineatthesametime,catalyzedbyarginaseSummary：1、InMitandcytosol；2、4ATPconsumption；3、Argininosuccinatesynthaseiskeyenzyme；4、Twomoleculesofnitrogenatoms:NH3，andAspEachintermediates;Carriersofone-carbonunits(3kinds)Tetrahydrofolate(H4folate)、S-adenosylmethionine、BiotinThe20aminoacidsaresynthesizedfromintermediatesof…Glycolysis,thecitricacidcycle,orpentosephosphatepathway9.NucleotideBiosynthesisTheoriginsofringatomsofpurinesandpyrimidinesTheatomsofthepurineringswerefoundtobederivedfromformate,CO2,Gly,Asp,andGln.TheatomsofthepyrimidineringswerefoundtobederivedfromAsp,GlnandHCO3-.10.DNAReplicationDNAreplicationSemiconservativereplication,connotation/proofinexamin