中南大学 生物化学 考研课件 ch10 膜转运 membrane transport

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1、BiochemistryForSpecialtyofBiotechnologyorBioengineeringatCSUMr.XIAJinlanCh.10MembraneTransportTransportofsmallmoleculesTransportoflargemoleculesorparticlesTransportofsmallmolecules小分子传输Passivediffusion被动扩散Simplediffusion简单扩散Facilitateddiffusion协助扩散Specializedmembr

2、anetransporter特定膜传输体（蛋白）Specializedmembranepores(self-study)特定膜孔（蛋白）Ionophore(self-study)离子氛ActivetransportsystemsDrivenbyATP由ATP驱动Na+/K+-ATPase,Ca2+-ATPase,H+/K+-ATPaseDrivenbylight由光驱动Drivenbyiongradients由离子梯度驱动Differingindiffusingprobabilityamongsmallmolecules小

3、分子间扩散性能比较(cm/sec)H2OUreaGlycerolTryptophanGlucoseCl-K+Na+HighpermeabilityLowpermeability10-210-610-810-1010-12HydrophobicmoleculesSmallunchargedpolarmoleculesLargeunchargedpolarmoleculesIonsO2CO2N2benzeneH2OureaglycerolglucosesucroseH+,Na+HCO3-,K+Ca2+,Cl-Mg2+Membr

4、aneproteininvolvementSpecificity特异性CoupledhydrolysisofATPCoupledtomovementofanionPassivetransport被动传输SimplediffusionFacilitateddiffusionActivetransport主动传输ATP-drivenactivetransportIon-drivenactivetransportGlucose,Cl-,HCO3-,etc.,PassivetransportActi

5、vetransportSimplediffusionFacilitateddiffusionTransportLargeunchargedmolecules,andsmallanionionsComparisoninmechanismbetweenpassivetransportandactivetransportChannelproteinCarrierproteinSimplediffusionChannel-mediatedCarrier-mediatedPassivetransport被动传输Activetrans

6、port主动传输TransportmoleculeComparisonofkineticsbetweenthetwoformsofpassivetransport---simpleandfacilitateddiffusion两种被动传输---简单扩散和协助扩散的动力学比较Simplediffusion:O2,H2O,CO2,Urea,ethanol,etc.Facilitateddiffusion:glucose,galactose,glycerol,etc.,Exampleoffacilitateddiffusion:

7、Diffusionofglucoseintoerythrocytes葡萄糖扩散进入红细胞是协助扩散的例子Erythrocyteglucosetransporter红细胞葡萄糖传输蛋白:Integralmembraneprotein,45kDa(整合膜蛋白)Uniporterprotein(单向转运蛋白)Traversesmembrane12timesofa-helixtoformacentralpore(a螺旋跨膜12次形成中心孔Changeinconformationfordiffusionofglucose扩散前后构象

8、变化PsNoteglucosetransportinE.Coliismediatedbythephosphoenolpyruvate:glucosephosphotransferasesystemGroupTranslocationforglucosetransportinsomebacteriaMem