《糖生物学》课程教学课件（讲稿）08 lock and key concept

Lock and Key

Lock and Key 1

an1.AsymmetricInduction

1. Asymmetric Induction 2

Modern concept of assymmetric inductionCNCN1HCNR*CHO+HC-OH +HO-CH11R*R*川I三HONCCNOHssm$SSSSSE1E2E'1E'2*R*RE = Nonbonded interaction energyWhen R* is dissymmetric,E2 + E'2E, + E'i3

Modern concept of assymmetric induction E = Nonbonded interaction energy When R* is dissymmetric, E1 + E'1 E2 + E'2

The preferential metabolismofthe dextro-enantiomer of tartaric acid is 15 years priortoFischer'sdoctoralstudiesCOOHCOOHCOOH111H-C-OHHO-C-HPenicilliumHO-C-H++FermentationproductsHO-C-HH-C-OHH-C-OHglaucum1COOHCOOHCOOHNaturalUnnaturaldl-TartaricacidI-TartaricacidFiG.2.LouisPasteur's preparation ofD-(levo)-tartaric acid

The preferential metabolism of the dextro￾enantiomer of tartaric acid is 15 years prior to Fischer’s doctoral studies

Anunderstandingof optical isomerismhadbeenprovidedin1874byvan'tHoff-LeBeltheory ofasymmetric carbonDissymmetricPlane of symmetryCOOHCOOHCOOHCOOH.HO-C-HH-C-OHHO-C-HH-CC-OH主HO-C-HHO-C-HH-C-OHH-C-OHCOOHCOOHCOOHCOOHMesoRacemateFiG.3.-Thebasic assumption forFischer's researchof the optical isomerism of sugarsAll previousobservationsinthesugargroup are insuchcomplete agreement with the theory ofasymmetric carbon thattheuseofthistheory seems justifiable

An understanding of optical isomerism had been provided in 1874 by van’t Hoff – Le Bel theory of asymmetric carbon All previous observations in the sugar group are in such complete agreement with the theory of asymmetric carbon that the use of this theory seems justifiable

On the way to explicit the configuration of glucose..HHHeatingwith quinolineHHHNH-C=OCOOHCOOHH.?.H-C-OHH-C-OHHO-C-H·..HO-C-HNH3+H-C-OHH-C-OH+...HO-C-HHO-C-HHO-C-H..CH2OHHO-C-HHO-C-HCH20HCH2OHl-Arabinosel-mannonicacidl-gluconicacid(Kiliani'sarabinocarbonicacid)

Heating with quinoline On the way to explicit the configuration of glucose

H-C=OCOOHCOOH.H-C-OHH-C-OHHO-C-HH20HCNHO-C-HNH3+H-C-OHH-C-OHHO-C-HHO-C-HHO-C-HCH2OHHO-C-HHO-C-HCH20HCH2OHl-ArabinoseI-mannonic acidI-gluconic acid(Kiliani'sarabinocarbonicacid)I-mannonic acid3 times greaterthangluco isomerThe simultaneous formationofthetwo stereoisomericproducts on additionof hydrogencyanide to aldehydes, which was observed here for the first time, is quite remarkable intheoreticalaswell asinpracticalterms.10c1ooaaoeaaeT62m95821e1uGuoenoa6i6o2o6cbkcc2onc0o2ak5ey

l-mannonic acid 3 times greater than gluco isomer

He accumulated pure substances with relativefigurations.And observed moreasymmetric inductionYield (%)Reference3420Mannonicacidl-Arabinose(50g)11Ca-gluconate8721d-Mannose (2kg)α-Mannoheptonicacid5122Gluconicacidlactoned-Xylose (40 g)35IdonicacidCOOHCHOCOOHH-OH-HHOHOHHO-1HHOHHO-HHITOH-HHOH--OHH--OHHOHCH20HCH2OHCH2OH

He accumulated pure substances with relative configurations. And observed more asymmetric induction

ehiralityIn 1894, " in the case of asymmetriSystems, the further synthesis occurs in.an.asymmetric sense

In 1894, “in "e case of asymme#ic sys%ms, "e &r"er syn"esis occurs in an asymme#ic sense.”( 9

2.Yeast FermentationseandEnzymes10

2. Yeast Fermentations and Enzymes 10