第一章 糖(1).pptVIP免费

BiochemistrySchooloflifescienceandtechnologyLiWenzhe1.ExistenceCarbohydratesarethemostabundantbiomoleculesonearth.2.Saccharidesplayavarietyofrolesinlivingorganisms:Energystorage(monosaccharidesandoligosaccharidesandpolysaccharides)Structuralroles(polysaccharides)Cellidentity(oligosaccharides)Carbohydrate/Saccharides3.DefinitionandclassificationofsaccharideCarbohydratesarepolyhydroxyaldehydesorketones,orsubstancesthatyieldsuchcompoundsonhydrolysis.Empiricalformula(CH2O)n;somealsocontainnitrogen,phosphorus,orsulfur.ClassificationofsaccharideThreemajorsizeclassesofcarbohydrates:MonosaccharidesSaccharideOligosaccharidesPolysaccharides:homopolysaccharide,heteropolysaccharide,glycoconjugate4.StructureofmonosaccharideStraight-chainstructureofmonosaccharidecarbonylgroup：醛糖aldose,酮糖ketosecarbonatomsinthebackbone：3,4,5,6,7……trioses,tetroses,pentoses,hexoses,andheptoses不对称碳原子(asymmetriccarbonatom)C*（chiralcarbon）Fisherprojection单糖构型configurationD，LnomenclatureTheenantiomers对映异构体ofglyceraldehydeConfigurationofmonosaccharide:basedon甘油醛glyceraldehydeComparetheconfigurationofthechiralcentermostdistantfromthecarbonylcarbon.Opticallyactiveisomers旋光异构Monosaccharidehasopticalactivity单糖具有旋光性左旋(levorotatory),“-”右旋(dextrorotatory),“+”旋光率(specificrotation)D、Lmeanconfiguration构型+、-meantheopticalactivityThepredominantmonosaccharidesinnature------------'D'configuration.Cyclic/Ringstructureofmonosaccharide环状半缩醛Formationofhemiacetalsandhemiketals.FisherprojectionformulatoHaworthperspectiveformulasα/β异头物anomerα,β--变旋现象(mutarotation)D,L异头碳Pyranose吡喃糖,Furanose呋喃糖5.Theconformationofmonosaccharide单糖的构象Pyranose：BoatChairConformationoffuranose:Envelopeform6.MonosaccharidesAreReducingAgentscanbeoxidizedbyferric(Fe3+)orcupric(Cu2+)ion.ReducingsugarsFehling’sreaction葡萄糖酸内酯7.ImportantmonosaccharidesandderivativesSixcarbonsugarProvidearapidsourceofATPPolymerform:Starch,cellul...