




版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
Chapter6VitaminandCoenzyme2023/7/251Vitaminsareorganicmoleculesthatareessentialtothebiologicalprocessesofhigherorganisms,butcannotbesynthesizedbytheseorganisms.Fat-soluble:vitaminsA,D,E,andKWater-soluble:Bcomplexvitamins,lipoicacidandvitaminC.2023/7/252Vitaminfunctions:Coenzymesincatalyzedreactions(derivatesofvitaminBs)Somevitaminsareconsideredashormones(vitaminsA&D)Antioxidants(vitaminsC&E)2023/7/253Avitaminosis
维生素缺乏症:beinglackofvitamin,obstacleofmetabolismdifferentvitamin,differentphysiologyfunction,differentsymptom2023/7/254Lipid-SolubleVitamins
Thefourlipid-solublevitamins-A,D,E,andK
类异戊二烯分子(异戊二烯构建分子生物合成)Althoughoneofthese,VitaminD,isultimatelyderivedfromcholesterol,Existedwiththelipidinfoods.AbsorbedintheintestineswiththelipidStoredinthebody,especiallyintheliver2023/7/255Afatsolublevitamin,Derivedfromβ-carotene胡萝卜素VitaminA2023/7/256ThealcoholformofvitaminA,retinol视黄醇,isthestorageforminthebodyThealdehydeform,retinal视黄醛,hasaroleinvision.Theacidform,retinoicacid视黄酸,functionsinembryonicdevelopment.VitaminAactstosomeextentinthebodyasanantioxidant抗氧化剂,protectingagainstoxidativedamage2023/7/257LackofVitA,暗处不能辨别物体,夜盲症眼球视网膜两类感觉细胞圆锥细胞:sensitivetobrightlightandcolour
杆细胞:sensitivetoweaklight,暗视觉视紫红质全反型视黄醛视蛋白11-顺视黄醛光分解暗合成同分异构酶2023/7/258VitaminD抗佝偻病维生素derivedfromcholesterol2023/7/259D3(mostabundantform),cholcalciferol胆钙化醇,inamimal
D2,麦角钙化醇,inplantVitaminDisnottechnicallyavitamin(notrequiredinthediet.Itarisesfromuv-photolysisof7-dehydrocholesterol7脱氢胆甾醇)VitaminDregulatescalciumandphosphorusmetabolism,有利于新骨的生成与钙化。2023/7/2510VitaminEAfatsolublevitamin,alsocalledα
-tocopherol生育酚,与动物生育有关2023/7/2511Anantioxidantprotectagainstoxidativedamageincellularmembranes.preventingtheattackofperoxides过氧化物,过氧化氢onunsaturedfattyacidsinmembranelipidsDeficiencyofvitaminEalsoleadstoothersymptoms,vitaminEprobablyplaysotherrolesasyetundiscovered.2023/7/2512inplantsasvitaminK12-甲基-1,4-萘醌的衍生物inanimalsasvitaminK2一般不易缺乏凝血维生素:具有促进凝血的功能促进肝脏合成凝血酶原(凝血因子II),调节另外三种凝血因子VII,IX,X的合成vitaminK2023/7/2513VitaminK2(Menaquinone)inanimalsVitaminK1(Phylloquinone)
inplants2023/7/2514Water-solublevitaminsthiamin(B1)硫胺素riboflavin(B2)核黄素niacin,niacinamide(PP,B3)烟酰(胺)pantothenicacid(B5)pyridoxin,pyridoxal(B6)biotin(B7)cyanocobalamin/hydroxycobalamin(B12)folicacid/folate(B9,VitaminM)lipoicacid/lipoate硫辛酸ascorbicacid(C)B-complexvitamins2023/7/2515CoenzymesSomeenzymesmayrequirethehelpofsomeothersmallmoleculeoriontocatalyzeareaction,Likeenzymes,coenzymesarenotirreversiblychangedduringcatalysis;theyareeitherunmodifiedorregenerated.Eachkindofcoenzymehasaparticularchemicalfunction.Someareoxidation/reductionagents,somefacilitategrouptransfers,andsoforth.Thenumberofimportantcoenzymesislimited,buteachofthemmaybeassociatedwithmanydifferentenzymes.2023/7/2516interconvertingUDP-glucoseandUDP-galactoseThemechanism:thehydroxylatposition4ischangedinstereochemicalorientationinvolvesoxidationofthehydroxyltoacarbonyl羰基asanintermediatestate.Carbonylintermediate-----excellentintermediatestateforinterconversionofthesugarsNAD+andNADHneverleavetheenzyme,theyarereducedandreoxidizedinacyclicfashion,providingatemporaryrestingplaceforelectronsandthehydrogenfromthesubstrate.2023/7/2517腺苷钴氨素甲基钴氨素2023/7/25181.VitB1&ThiaminePyrophosphate(TPP)焦磷酸硫胺素,辅羧酶含硫的噻唑环thiazole含氨基的嘧啶环pyrimidine
抗脚气病维生素twoheterocyclicrings2023/7/2519Mechanismofaction–
TPP:thiazoleisthereactivemoiety,carbanion
负碳离子.
Carbanion
canattackthecarbonylcarbonofa-ketoacids,suchaspyruvate,givinganadditioncompoundTPPisusedasacoenzymeforalldecarboxylationsof-ketoacidsthiamine(VitaminB1)+ATPpyrophosphategroupTPP+AMPa2023/7/2520羟乙基-TPP2023/7/25211.Carbanionattackonthecarbonyl-carbonofa-ketoacidstoyieldanadditioncompound
加成化合物2.Decarboxylationoftheadditioncompoundwiththethiazoleringactingasanelectronsinkinformingaresonance-stabilizedeneamine.3.Protonationoftheeneaminetoformanactiveacetaldehydecalledhydroxyethyl-TPP.4.Thedecarboxylatedcompoundisreleased,yieldingfreeTPP.5.Carbanionformation羟乙基-TPP2023/7/2522
pyruvate
decarboxylase
丙酮酸脱羧酶,pyruvate
dehydrogenase丙酮酸脱氢酶,branchedchaina-ketoaciddehydrogenase
glutarate
dehydrogenase酮戊二酸脱氢酶Transketolase
转羟乙醛酶,转酮醇酶.,SomeenzymesthatuseTPP:2023/7/2523维生素B1缺乏,糖代谢受阻,丙酮酸积累血、尿、脑组织丙酮酸含量增多,出现多发性神经炎,皮肤麻木,心力衰竭,肌肉萎缩。下肢浮肿等脚气病2023/7/2524nicotinamide烟碱coenzymes
nicotinamideadeninedinucleotide(NAD+)
nicotinamideadeninedinucleotide
phophate(NADP+)2.VitPP抗癞皮病维生素烟酸nicotinicacid烟碱nicotinamide2023/7/2525NADHisacarrierofelectronsproducedinbiologicaloxidations.twoformsNADH----reducedformofthemolecule(carrieselectrons)
NAD+-----oxidizedformofthemolecule(lackselectrons)2023/7/2526NADPHisanelectroncarrier.Twoforms:NADPH----reducedformofthemolecule(carrieselectrons)
NADP+-----oxidizedformofthemolecule(lackselectrons)NADPHisproduced-------pentosephosphatepathwayInplants,photosynthesisisanothersourceofNADPH.2023/7/2527NADHVSNADPHNAD+/NADH:donateselectronstotheelectrontransportsystemforenergygeneration氧化途径(分解代谢)中电子受体NADP+/NADPH:donateselectronstobiosyntheticreactions还原途径(合成代谢)电子供体2023/7/25283.Riboflavin核黄素
核醇ribitol
7,8-二甲基异咯嗪isoalloxazinering
Riboflavin(vitaminB2),isacomponentoftheflavincoenzymes,FADandFMN2023/7/2529SiteN1andsiteN5hasactivedoublebondrespectively2023/7/2530FADisanimportantacceptorofelectronsFADistheoxidizedformofthemolecule(lackselectrons).
FADH2isthereducedform(carrieselectrons)Flavincoenzymes:flavinadeninedinucleotide(FAD)
flavinmononucleotide(FMN)2023/7/2531
FADandFADH2functioninmanyoxidationreactionsSuccinate+FAD(enzymebound)<=>Fumarate+FADH2(enzymebound)FADisboundcovalentlytotheenzymeproteinthroughaspecifichistidineresidue2023/7/2532Theabilityoftheringsystemofriboflavintoexistasasemiquinoneallowstheflavincoenzymestoacceptelectronseithersinglyorinpairs2023/7/2533CommonacceptorsofelectronsincludetheFAD,FMN,NAD+,NADP+NAD+,NADP+canacceptelectronsinpairs,eachpairofelectronsfromNADHresults2.5ATPsFADandFMNcanalsoacceptsingleelectronsviaformationofasemiquinoneintermediate,
eachpairofelectronsdonatedbyFADH2resultsin1.5ATPs2023/7/25344.PantothenicacidandCoenzymeA(CoAorCoASH)
Pantothenicacid
coenzymeA----acyl-carriermoiety2023/7/2535β
-Mercaptoethylamine巯基乙胺----acylgroupsareattached2023/7/25363`,5`-ADPAfreethiolisthefunctionallysignificantpartofthecoenzymemoleculeTherestofthemoleculeprovidesenzymebindingsites3`,5`-ADP:识别部位,增加CoA亲和性和专一性2023/7/2537acylatedderivatives,suchasacetyl-coenzymeA,theacylgroupislinkedtothethiolgrouptoformanenergy-richthioestertheacylatedformsofcoenzymeA:acyl
-
CoA,CH3CO-SCoAtheunacylatedform:CoA-SH.2023/7/2538energy-richnatureofthioestersVSordinaryesters2023/7/2539CommonmetabolicreactionsinvolvingCoenzymeAareshownbelow.1.
Acetate+CoASH+ATP<=>Acetyl-CoA+AMP+PPi
(catalyzedbyAcetateThiokinase硫激酶).2.
Pyruvate+NAD++CoASH<=>Acetyl-CoA+NADH+CO2(catalyzedbyPyruvate
Dehydrogenase)3.
3-Ketoacyl-CoA+CoASH<=>Acyl-CoA(less2carbons)+Acetyl-CoA(catalyzedbyThiolase硫解酶).2023/7/25404.
Malonyl-CoA+ACP<=>Malonyl-ACP+CoASH(catalyzedbyMalonyl-CoA-ACP
Transacylase)5.
Acetyl-CoA+ACP<=>Acetyl-ACP+CoASH(catalyzedbyAcetyl-CoA-ACPTransacylase)6.
Acyl-CoA+Carnitine<=>Acyl-Carnitine+CoASH(catalyzedbyCarnitine
AcyltransferaseI)7.
Acyl-Carnitine+CoASH<=>Acyl-CoA+Carnitine(catalyzedbyCarnitine
AcyltransferaseII)肉(毒)碱2023/7/25415.VitB6&PyridoxalPhosphate(PLP)VitB6吡哆醛嘧啶衍生物吡哆醇吡哆胺活性形式:磷酸吡哆醛(PLP)氨基酸代谢中多种酶的coenzyme
磷酸吡哆胺2023/7/2542Pyridoxalphosphateparticipatesin
transaminations
转氨作用,
decarboxylations
去碳酸基,numerousmodificationsofaminoacidsidechains2023/7/2543PLP-containingenzymesfunction:SchiffbasebetweentheaminoacidandcoenzymeAcation(ametaloraproton)isessentialtobridgethephenolateionofthecoenzymeandtheimino
亚氨基的nitrogenoftheaminoacid.Thisbridgingmaintainstheplanarityofthestructure,essentialforcatalysis.2023/7/2544aquinoid
醌型structureDependingonthebondlabilized
使不稳定,formationofthealdimine
醛亚胺canleadtoatransamination,todecarboxylation,toracemization,ortonumeroussidechainmodifications2023/7/25456.VitaminB12Thepresenceofcobaltandamidenitrogens-----thenamecobamidesorcobalamins
钴胺素,钴胺酰胺2023/7/2546Themetalcobaltiscoordinatedcorrinring咕啉环,Thecyanide氰化物attachedtothecobalt辅酶:5`-脱氧腺苷钴胺素甲基钴胺素About15differentB12-requiringreactionsareknown核苷酸还原成脱氧核苷酸isomerizationsmethylgrouptransfer2023/7/2547B12coenzymes
methylgroup5'-adenosylmoietyCNlinkedtocobaltthefirstknownorganometallicsvitamininmetabolism2023/7/2548thesynthesisofmethionine
甲硫氨酸fromhomocysteine高半胱氨酸2023/7/2549B12-requiringreactionsinvolve:(1)methylgrouptransfer(2)核苷酸还原成脱氧核苷酸byaribonucleotide
reductaseofLactobacillus乳酸菌.(3)isomerizations:exchangeacarbon-boundhydrogenwithanothercarbon-boundfunctionalgroup甲基丙二酰-CoA2023/7/25507.Biotin
噻吩环双环化合物尿素戊酸Biotin2023/7/2551Biotinisavitaminandacoenzymelinkedcovalentlytocarboxylaseenzymesthroughtheε-aminonitrogenoflysine生物胞素复合物associatedwithenzymesperformingcarboxylationreactions2023/7/2552Enzymescontainingbiotin:acetylCoA
carboxylaseAcetyl-CoA+ATP+HCO3-<=>Malonyl-CoA丙二酸单酰~
SCoA+ADP+Pi+H+pyruvate
carboxylasePyruvate+HCO3-+ATP<=>Oxaloacetate+ADP+Pi+H+
Carbamoyl
氨基甲酰phosphatesynthetaseIIGlutamine+ATP+HCO3-<=>Glutamate+CarbamoylPhosphate+ADP2023/7/2553Biotin--abundantinmanyfoodsandissynthesizedbyintestinalbacteriadeficiencyisrare,butcausedbyadietrichinraweggsEggwhitescontainalargeamountoftheproteinavidin
(Mr70,000),whichbindsverytightlytobiotinandpreventsitsabsorptionintheintestine.Theavidinofeggwhitesmaybeadefensemechanismforthepotentialchickembryo,inhibitingthegrowthofbacteria.Wheneggsarecooked,avidinisdenatured(andtherebyinactivated)alongwithallothereggwhiteproteins.Avidin--------biotin(Aproteincovalentlybound)affinitychromatography2023/7/2554碟酸碟酰谷氨酸6-甲基碟啶对氨基苯甲酸8.FolicAcid(Pteroylglutamicacid碟酰谷氨酸)
吡嗪2023/7/2555Folicacidisformedfromthreedistinctmoieties:(1)6-methylpterin6-甲基喋啶(2)p-aminobenzoicacid(PABA),对氨基苯(甲)酸
(3)glutamicacid
3-8ormoreglutamateresiduespermoleculeofvitamin2023/7/2556folate----------------activeforms(tetrahydrofolate)dihydrofolate
reductase(DHFR)--NADPH-specificenzyme2023/7/2557tetrahydrofolate---------generationandutilizationofsingle-carbon
methyl甲基,
methylene
亚甲基,
formyl甲酸基N5,N10orboth--single-carbon
2023/7/25582023/7/2559ActivityofDHFRisblockedbyfolateanalogs
aminopterin
氨碟呤
amethopterin氨甲碟呤抗肿瘤药物嘌呤&胸腺嘧啶肿瘤生长氨碟呤氨甲碟呤2023/7/2560FolicaciddeficiencyDNAsynthesisCelldivisionisslow,volumeincreasemegaloblasticanemia巨红细胞性贫血2023/7/25619.lipoicacid闭环二硫化物形式开环还原形式Lipoic
acid+Lys
硫辛酰胺复合物lipoamideanamidebondlinkingthecarboxylgroupoflipoicacidtoalysineδ-aminogroupoftheenzyme.2023/7/2562LipoicacidinamidelinkagewithaLysresidue2023/7/2563Lipoate
Twothiolgroups-----reversibleoxidationtoadisulfidebond(-S-S-)
electronhydrogencarrieracylcarrier2023/7/25642023/7/256510.VitaminC(AscorbicAcid)
awater-solubleenzymeacidicactsasapotentantioxidant,protectingagainstdamagebyreactiveoxygenspecies(2,3site---OH)L-ascorbicAciddehydro-ascorbate22023/7/2566AntioxidantssuchasvitaminA,vitaminC,andvitaminEprovideprotectionagainstoxidativedamagefromreactiveoxygenspecies,suchassuperoxides,hydroxylradicals,hydrogenperoxide.2023/7/2567
aroleinmakingcrosslinksbetweenaminoacidsincollagen胶原蛋白VitaminCCollagenfibers----formthematrix,orcement,materialinbone,onwhichthemineralconstituentsprecipitate.animportantconstituentoftendonsandskin2023/7/2568Collagen:widespreadmodification
prolinetohydroxyproline
lysine
tohydroxylysineThehydroxylation羟基化作用reactionsincollageninvolvevitaminC羟化酶维持活性所必需的辅因子2023/7/2569prolyl4-hydroxy
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 中国硝酸锰项目商业计划书
- 2025年中国钛靶材项目投资计划书
- 中国作物秸秆肥项目投资计划书
- 中国金属加工液项目商业计划书
- 巴彦淖尔市人民医院内分泌相关基因报告解读考核
- 运城市中医院放射性肠炎护理考核
- 朔州市中医院个体化治疗方案制定考核
- 大同市中医院社区护士岗位胜任力考核
- 廊坊市中医院泌尿系肿瘤的多学科诊疗能力考核
- 中国乳聚丁苯橡胶项目投资计划书
- GB/T 17622-2008带电作业用绝缘手套
- 部编版六年级语文上册-第三单元习作:-让生活更美好课件
- 耳鼻喉头颈外科考试题库及答案
- 感染性心内膜炎内科学第版
- 六年级上册科学课件-3.23《传动的齿轮》 l 粤教版(共25张PPT)
- 播音主持自我介绍范文八篇
- 材料分析测试技术 第2版 周玉 课后答案1-4章.khda
- 喀斯特地貌精讲课件
- 城市文化与节事活动的的策划与管理肖岱柏课件
- 四层电梯plc控制
- 水电站课程设计 40
评论
0/150
提交评论