Vitamin and coenzyme(1).pptVIP免费

VitaminandCoenzymeVita:lifeAmine:containingN–(1stvitaminscontainednitrogen)Vitaminsareorganic,essentialnutrientsreq’dinminuteamountstoperformspecificfunctionsthatpromotegrowth,reproduction,orthemaintenanceofhealth&lifeVitaminsHowvitaminsdifferfromtheHowvitaminsdifferfromtheenergy-yieldingnutrientsenergy-yieldingnutrientsStructure–Vitaminsareindividualunits,notlongchainsFunction–Donotyieldenergybutassistinreleasingenergyfromcarbohydrates,fatsandproteinsFoodcontent–Smallamountsneededdaily(microgramsandmilligrams)OtherCharacteristicsOtherCharacteristicsOrganicNature–CanbedestroyedsofoodneedstobehandledwithcaretoavoidlossinstorageorcookingSolubility–Hydrophilic:watersoluble•BvitaminsandvitaminC,lipoicacid–Hydrophobic:fatsoluble•VitaminA,D,EandKWater-Soluble1.Absorbeddirectlyintoblood2.Transportedfreely3.Circulateinbodyfluids4.Kidneysremoveexcess5.Unlikelytoreachtoxiclevels6.Frequent,smalldosesreq’d(1-3days)Fat-Soluble1.Absorbedintolymph,thenintoblood2.Manyneedproteincarriersfortransport3.Storedincellswithfat4.Noteasilyexcreted5.Reachestoxiclevelswhenconsumedinexcess6.Periodicdosesreq’dWaterandFat-SolubleVitaminsVitaminfunctions:Coenzymesincatalyzedreactions(derivatesofvitaminBs)Somevitaminsareconsideredashormones(vitaminA&D)Antioxidants(vitaminsC&E)Someenzymesmayrequirethehelpofsomeothersmallmoleculeoriontocatalyzeareaction,•coenzymesarenotirreversiblychangedduringcatalysis;•Eachkindofcoenzymehasaparticularchemicalfunction.•Thenumberofimportantcoenzymesislimited,buteachofthemisassociatedwithmanydifferentenzymes.Coenzymes•UDP-galactoseconvertingtoUDP-glucose•-OHatposition4changesitsstereochemicalorientation•-OHchangestoacarbonyl羰基asanintermediatestate.•NAD+andNADHascoenzyme:neverleavetheenzyme,reducedandreoxidizedinacyclicfashion,providingatemporaryrestingplaceforelectronsandthehydrogenfromthesubstrate.AvitaminosisAvitaminosis维生素缺乏症维生素缺乏症•Beinglackingofvitamin,obstacleofmetabolism•Differentvitamin,differentphysiolog...