Chap2_Carbohydrates

1、1Chapter 2. CarbohydratesP.235第三代新生物技术-糖生物工程来源：中国科学报 日期: 2012年07月27日2继基因工程、蛋白质工程之后，糖生物工程已成为最引人注目的生物技术新领域，被国际科技界称为第三代新生物技术。糖是生物界储量丰富的生物资源，是蕴藏大量生命信息的生命大分子，参与调控包括生殖、生长、发育、免疫等几乎全部生命过程。糖制剂还具有调节肠道生态平衡、促进营养物质消化吸收、调节免疫的特点。正在被应用于饲料添加剂、生物肥料、生物农药。具有安全无毒、高效及不易产生抗药性等特点。3I. Introduction41. ExistenceI. Introductio

2、nP.152. FunctionI. IntroductionP.163. Definition葡萄糖果糖甘油醛二羟基丙酮Carbohydrates are polyhydroxy aldehydes or ketones (多羟基醛/多羟基酮) or substances that yield such compounds on hydrolysis.7Three major classes of carbohydratesI. Introduction85. Characteristic chemical features (化学通性)I. IntroductionP.29II. Mono

3、saccharides101. Two families: Aldoses & ketosesAldoses(醛糖)Ketoses(酮糖)II. Monosaccharides甘油醛二羟丙酮丙糖己糖112. StereochemistryII. Monosaccharides12(1) Plane-polarized light (平面偏振光 )Plane-polarized light (平面偏振光) a light with its electric vector vibrating on a specific plane called the plane of polarizat

4、ion (偏振面)Polarimeter (偏振器偏振器) an instrument used to measure optical activity.Polarimeter(偏光计)Light source(non-polarized light)非偏振光Polarizer(偏光器)Plane-polarized light(平面偏振光 )Sample tube棱镜Plane of polarization rotated(偏振面发生了旋转)棱镜13(2) Optical activity (旋光性)A material which can rotate the plane of the

5、plane-polarized light is called to have optical activity, and this material is an optically active substance. (能使平面偏振光的偏振面发生旋转的物质被称为具有旋光性)t = t c lRotation(旋光度)Specific rotation (比旋)Concentration (浓度, g/ml)Length (dm)Wavelength (波长, nm)TemperatureRotation 14(3) Chirality (手性)Optically active molecul

6、e Chiral molecule(旋光性分子 手性分子)Optical activity (旋光性) Chirality (手性)Chiral centers(手性中心)?15True or false:vChiral molecules are always optically active.( )vOptically active molecules always have chiral centers.( )vChiral molecules have always chiral centers.( )vMolecules with chiral centers are always

7、chiral.( )II. MonosaccharidesP.3CHOC*OHHC*HHOC*OHHC*OHHCH2OHn = 4 24 = 16 isomers16(4) Fischer projections (Fischer投影式)投影式甘油醛(+)()RSDL透视式II. MonosaccharidesP.417CHOOHHHHOOHHOHHCH2OHCHOHHOOHHHHOHHOCH2OHD-(+)-GlucoseL-(-)-GlucoseD or L refers to the configuration of the C* farthest from the carbonyl C

8、.4 C* 24 = 16 isomers8 D-forms8 L-forms18Aldoses (醛糖)19Ketoses (酮糖)II. Monosaccharides20Two systems of specifying the absolute configurations(绝对构型的两种表达体系)Group 4 with the lowest priorityD/L referring to the configuration of the molecule (对整个分子而言)R/S referring to the configuration of a specific C* (对

9、单个C*原子而言)D-glucose2R,3S,4R,5R-aldohexose (己醛糖) R/S convention priority rulesCHOCOHHCHHOCOHHCOHHCH2OH123456+/ referring to the optical activity of the chiral molecule(指分子的旋光性，与分子或原子的构型无直接关系)21qD-forms of monosaccharides predominate in nature.qL-Monosaccharides also exist in nature.qD-glucose is the e

10、nantiomer of L-glucose. But D-aldohexoses (己醛糖) are not necessarily enantiomers of all of their L-isomers.II. MonosaccharidesThe above four are stereoisomers.CHOCOHHCHHOCOHHCOHHCH2OH123456CHOCHHOCOHHCHHOCHHOCH2OH123456CHOCHHOCHHOCOHHCOHHCH2OH123456D-GlucoseL-GlucoseD-MannoseCHOCOHHCOHHCHHOCHHOCH2OH1

11、23456L-MannoseEnantiomerEnantiomerDiastereomerDiastereomer223. StructureII. Monosaccharides23Epimers two diasteroisomers that differ only in the configuration around one carbon atom.Epimers are usually diastereomers. (差向异构体多是非对映异构体)差向异构体是仅有一个手性碳原子的构型不同的Anomers Two monosaccharides that differ only in

12、 their configuration about the hemiacetal or hemiketal carbon atom.Anomers are epimers. (异头物是差向异构体)差向异构体.差向异构体异头物24Hemiacetals (半缩醛) and hemiketals (半缩酮)醛酮半缩醛半缩酮缩醛缩酮Addition(加成反应)Substitution(取代反应)25Cyclic structure (1): FormationII. MonosaccharidesP.9异头物-Anomer-Anomer-D-吡喃葡糖-D-吡喃葡糖Anomeric C (异头碳)2

13、6Cyclic structure (2): Haworth projections (Haworth透射式)When lining up clockwisely:-CH2OH above the ring - D-configuration-CH2OH below the ring -L-configuration-OH at the anomeric C and -CH2OH:On the opposite side On the same side D or L? or ?CHOCOHHCHHOCOHHCOHHCH2OHOHOHHOHHOHHOHCH2OHHOHOHOHHHOHHOHCH

14、2OHH123456123456123456Fischer projection formulasHaworth projection formulasP.10TopBottom27-D-glucoseD-glucose(Linear)-D-glucose36%0.024%64%20D = +112.2o20D = +18.7oCyclic structure (3): , anomersMutarotation (变旋变旋)：在水溶液中糖的-和-异头物之间互相转化导致其旋光度发生变化的现象146oC m.p.148-155oC m.p.II. Monosaccharides+52.6oP.8

15、-9-D-glucose and -D-glucose are not enantiomers to each other; they are epimers and anomers with different properties.(-D-glucose和-D-glucose不是互为对映异构体，是差向异构体和异头物，具有不同的物理/化学性质。)28Mutarotation (变旋)36%20D = +112.2o146oC m.p.64%20D = +18.7o148-155oC m.p.(0.024%)At equilibrium, 20D = +52.6o29OHOHOHHHOHHOH

16、CH2OHHOOHHHOHHHOHHOOHHHOHOHHOHHHCH2OHCH2OHOH-D-Glucose-L-GlucoseFlipping30Cyclic structure (4): Pyranoses & furanosesPyranoses（吡喃糖）Furanoses（呋喃糖）II. MonosaccharidesP.1031CHOCOHHCHHOCOHHCOHHCH2OHOHOHHOHHOHHOHCH2OHHOHOHOHHHOHHOHCH2OHH123456123456123456CH2OHCOCHHOCOHHCOHHCH2OH123456OOHOHOHCHOHCH2OH

17、OOHOHOHCHOHCH2OHOHOHCH2OHOHOHOHHHOHOHOHCH2OHOHOHHH123456123456OOHOHCH2OHOHCH2OHOOHOHOHCH2OHCH2OH123456123456123456123456-D-吡喃葡糖-D-吡喃葡糖-D-呋喃葡糖-D-呋喃葡糖-D-吡喃果糖-D-吡喃果糖-D-呋喃果糖-D-呋喃果糖D-glucoseD-fructose32Cyclic structure (5): ConformationFor D-glucose, -form is more stable than -form.For other aldohexoses,

18、 -form is more stable than -form.OHOHHHOHHHOHOH2CHOHOOHHOHHOHOHHHCH2OHHTwo possible chair conformations of -D-glucoseII. MonosaccharidesP.13334. PropertiesII. Monosaccharides34Chemical propertiesII. MonosaccharidesP.15CHOCOHHCHHOCOHHCOHHCH2OH1234563521%2.5%II. Monosaccharides63.5%CCOHHCHHOCOHHCOHHCH

19、2OHOHCCOHCHHOCOHHCOHHCH2OHOHHD-GlucoseD-Ba(OH)2CH2OHCCHHOCOHHCOHHCH2OHOD-FructoseD-CCHHOCHHOCOHHCOHHCH2OHOHD-MannoseD-P.15-1636Chemical Properties (2): OxidationCH=OCH2OHOHOHOHHOCOOHCH2OHOHOHOHHOCH=OCOOHOHOHOHHOCOOHCOOHOHOHOHHOCu2+OH-Dehydrogenase(脱氢酶)HNO3Aldonic acid醛糖酸Uronic acid糖醛酸Aldaric acid醛糖二

20、酸Sugar acids(糖酸)Br2/H2O37Oxidizing agents (氧化剂): H2O2, Ag+, Fe3+, Cu2+Fehling reagents: tartrate (酒石酸钾钠)，NaOH, CuSO4Benedict reagents: citric acid (柠檬酸), Na2CO3, CuSO4Reducing sugar (还原糖):Capable of reducing oxidizing agents (可以还原以上的氧化剂)All aldoses and many ketoses are reducing sugars (所有醛糖和多数酮糖)Fru

21、ctose is a reducing sugar (果糖是还原糖)CHOOHHHHOOHHOHHCH2OH+ 2Cu2+ + 4OH-COOHOHHHHOOHHOHHCH2OH+ 2CuOH + H2OAldoseAldonic acidCu2OA qualitative test for reducing sugars (还原糖还原糖)P.16(Red precipitate)还原糖的定性检测38Measurement ofBlood Glucose ConcentrationOHOHHOCH2OHOCH-OH + O2HHHHOHOHHOCH2OHOHHHH=O + H2O2Glucos

22、e oxidaseD-GlucoseD-Glucono-lactone(葡萄糖氧化酶)39Chemical Properties (2): Oxidation (continued)CHOOHHHHOOHHOHHCH2OHCOOHOHHHHOOHHOHHCH2OHBr2/H2OpH 6.0CH=OCH2OHOHOHOHHOHHHHHCOOH4 HCOOHHCHO+IO4-This reaction is specific for aldoses.(此反应只适用于醛糖)This reaction is useful in providing structural information (此反应

23、可帮助分析糖的结构)II. Monosaccharides401,2-linkage1,4-linkage1,6-linkageOxidation by IO4-OOHOOCH2OHOHO=HCO=HCOOOCH2OHIO4-H2CH2COOOCH2OHHOHONaBH4H2CH2COOHOHCH2OHHOHOH2CH2CCH=OOHOHCH2OHHOHOCH2OHHCCH2OHOHCHOHCCH2OHOH+H+OOOOHOHCH2OHIO4-NaBH4CH2OHHOHCCHOHCHOCH2OH+H+CHOOHCOOOCH2OHCH2H2COOOCH2OHOHOHCH2H2COOHOHCH2O

24、HOHOHCH2H2CCHOOHOHCH2OHOHOHCH2OHOOHOOHOHCH2IO4-NaBH4CH2OHHCCHOCH2OH+CH2OHOOHCOHCOOCH2O+ HCOOHCH2H2COOCH2+ HCOOHOHHOOOCH2H2COOHCH2OH+ HCOOHOHHOCH2H2CCHOOHCH2OH+ HCOOHOHHOOH+ HCOOHH+P.7241Chemical Properties (3): ReductionCH=OCH2OHOHOHOHHOCH2OHCH2OHOHOHOHHOCH2OHCH2OHOHHOCH=OCH2OHOHHOHOHONaBH4NaBH4180o

25、RotationD-葡萄糖D-葡萄醇L-古洛糖L-古洛醇C=OCH2OHHOOHOHCH2OHC=OCH2OHHOOHCH2OHHOHOHOD-果糖L-山梨糖NaBH4NaBH4Sugar alcohols(糖醇)42Sugar alcohols (糖醇)CH2OHCH2OHOHOHOHHOD-Glucitol(D-葡萄醇)Sorbitol (山梨醇）CH2OHCH2OHOHOHHOD-Mannitol(D-甘露醇)HOCH2OHCH2OHOHOHHOD-Xylitol(D-木糖醇)CH2OHCH2OHOHGlycerol(甘油醇)HHHHHHHHHHHHII. Monosaccharides

26、43Chemical Properties (4): Formation of osazone（糖脎）CHOOHHHHOOHHOHHCH2OH3 C6H5-NH-NH2+CHN=NHC6H5HHOOHHOHHCH2OHN-NHC6H5+ C6H5-NH2 + NH3 + 2H2OHAcpH4-6苯肼苯脎 (黄色晶体)This reaction is useful in characterizing reducing sugars (此反应用于鉴定还原糖).Yellow crystals withv Different crystal shapesv Different melting poin

27、tsII. Monosaccharides44Chemical Properties (5): Sugar Esters & Sugar Ethers(糖酯和糖醚)OHHOHHOHHOHHOHOHOHH3COCOHH3COCOHHOCOCH3HOCOCH3OCOCH3(CH3CO)2OPyridine, 0oCOHHOHHOHOHOHHHOHOHH3COHH3COHOCH3OCH3HHOCH31). CH3SOCH2Na2). CH3IAcetylation(乙酰化)Methylation(甲基化)Phosphorylation(磷酸化)OHHOHHOHOHOHHHOHOHHOHHOH

28、OHOHHHOPO3-+ ATP+ ADPP.1945OHOHHOCH2OHHHHOHHOOHOHHOCH2OHHHHO-CH3HOHemiacetal(半缩醛)Acetal(缩醛)Glycone (糖基)Aglycone(配基)Glycosidic bond(糖苷键)Chemical Properties (6): Glycoside (糖苷)Glycoside (糖苷)Monosaccharide (单糖)II. MonosaccharidesGlycosidic bond is unstable under acidic conditions.(糖苷键在酸性条件下不稳定)P.19H+46

29、Difference between a monosaccharide and its glycoside:Glucose (单糖): Hemiacetal (半缩醛) reducing sugar (还原糖)Glycoside (糖苷):Acetal (缩醛) non-reducing sugar (非还原糖)Methyl- -D-glucosideMethyl- -D-glucosideD-GlucoseCHOOHHHHOOHHOHHCH2OHOHHOHHOHOCH3OHHHOHOHHOHHOHHOHHOCH3OHCH3OHHCl47Chemical Properties (7): Deh

30、ydration5-Hydroxymethyl furfural5-羟甲糠醛CHOCOHHCHHOCOHHCOHHCH2OHCHOCOHCHCOHHCOHHCH2OHCHOCOCHCOHHCOHHCH2OHCHCHOCOCCHCOHHCH2OHCHOOCHOHOH2CHOHCHOHOH2C-H2O-H2ODifferent furfurals react with polyphenols to generate different specific colors, therefore this reaction is useful in characterizing the monosacch

31、arides.(用于单糖的定性检测)II. MonosaccharidesP.2048OCHOHOH2COHOH-H2O(Seliwanoff test)糠醛-萘酚蒽酚红紫色缩合物 (Molish test)糠醛蓝绿色复合物 (蒽酚反应)5-羟甲糠醛-H2OOCHOOHOHHOCH3OHHO (Bial test)鉴定酮糖鉴定戊糖鉴定糖类测定总糖量糠醛49II. MonosaccharidesP.2250Important monosaccharides甘油醛二羟丙酮丙糖己糖戊糖What is honey?II. Monosaccharides51Some hexose derivatives

32、 important in biologyII. Monosaccharides52Sugar phosphate（糖的磷酸酯）Adenosine triphosphate (ATP)II. MonosaccharidesNNNNNH2OOHOHHHHHOPOO-OPOO-OP-OO-O53III. Oligosaccharides (寡糖)541.Glycosidic bonds (糖苷键)麦芽糖III. OligosaccharidesReducing end()Nonreducing end()55Maltose （麦芽糖）Glucose-1,4-glucoseCellobiose（纤维

33、二糖）glucose-1,4-glucoseIsomaltose（异麦芽糖)Glucose- -1,6-glucoseOOHOOHOHCH2OHCHOHOOHOHOHCH2OOHOHOHCH2OHCHOOHOHCH2OHOOHOOHOHOHCH2OHOOHOHCH2OHOCHOHO-D-glucopyranosyl-(14)-D-glucopyranoseO-D-吡喃葡糖基-(14)-D-吡喃葡糖Glc (14) Glc(14) (16) (14)562. Nomenclature (命名)-乳糖半乳糖-葡萄糖Gal (14) Glc蔗糖葡萄糖-果糖Glc (12) FruFru (21) G

34、lc海藻糖葡萄糖-葡萄糖Glc (1 1) GlcNonreducing sugarsReducing sugarsO-D-吡喃半乳糖基-(14)-D-吡喃葡糖P.24357583. Some oligosaccharide examplesIII. OligosaccharidesP.36-4059Cyclodextrins (环糊精)-OH at C-6-OH at C-2, C-3HydrophobicInside(内部疏水)HydrophilicOutside(外部亲水)60IV. Polysaccharides (多糖)611. ExistenceIV. Polysaccharide

35、s622. ClassificationIV. Polysaccharides633. Homopolysaccharides (同多糖)Function(功能)PolymerStructure(结构)Glycosidic bond(糖苷键)Size(No. of units)Source(来源)EnergyStarch (淀粉)Plantsstorage-Amylose(直链淀粉)Linear(14)Glc50-5000贮存多糖Amylopectin(支链淀粉)Branched(14)Glc(16)GlcUp to 106Glycogen(糖原)Branched(14)Glc(16)GlcU

36、p to 50000AnimalsStructuralCellulose(纤维素)Linear(14)GlcUp to 15000Plants结构多糖Chitin(壳多糖)Linear(14)GlcNAcVery largeAnimals64Starch: Amylose & amylopectin（直链淀粉 & 支链淀粉）P.41 14A short segment of amylose (直链淀粉)( 16)( 14)A segment of amylopectin (支链淀粉)65Amylose （直链淀粉）The most stable three-dimensiona

37、l structure for the (14)-linked chains of starch and glycogen is a tightly coiled helix, stabilized by interchain H bonds.66A cluster of amylose and amylopectin67Amylose & amylopectin (直链和支链淀粉)P.42Fig.1-2468Cellulose（纤维素）IV. PolysaccharidesP.4569CelluloseIV. PolysaccharidesP.46Fig.1-27Chitin (壳多

38、糖)A linear homopolysaccharide composed of N-acetylglucosamine residues in (14) linkage.Principal component of the hard exoskeletons of arthropodsThe 2nd most abundant polsaccharide in nature1 billion tons are produced each year in biosphereDifferent from cellulose in: C-2Similar to cellulose in: 14

39、glycosidic bond linkage Extended fibers Cannot be digested by vertebrates70714. Hetereopolysaccharides（杂多糖）IV. Polysaccharides72Agar (琼脂)Agarose (琼脂糖)Agaropectin (琼脂胶)IV. PolysaccharidesP.49Agarose (琼脂糖)Remarkable gel-forming property useful in biochem lab.Double helical structure to trap water in the central cavityUsed as support for electrophoresisUsed as support for gel-filtration chromatography Sepharose (琼脂糖凝胶)Used to form a surface fo