糖酵解作用ppt课件.ppt

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1、华中科技大学生命科学与技术学院生物物理与生物化学研究所陆　婕生物化学第22章糖酵解作用Chapter22Glycolysis葡萄糖血G转运体细胞充足氧有氧氧化(TCA)CO2、H2O缺氧糖酵解(EMP）乳酸（or乙醇）磷酸戊糖途径提供五碳糖和NADPH合成代谢糖原乳酸、Ala糖异生糖酵解（glycolysis)是指葡萄糖在无氧条件下分解生成乳酸并释放出能量的过程。又称EMP途径。1.酵解途径详解2.酵解过程中能量的产生—ATP的合成3.丙酮酸的去路4.酵解途径的调节5.其它糖进入酵解的途径TheDevel

2、opmentofGlycolysis1897,EduardBuchner(Germany),accidentalobservation:sucrose(asapreservative)wasrapidlyfermentedintoalcoholbycell-freeyeastextract.（1907NobelPrizelaureate)1900s,ArthurHardenandWilliamYoung(GreatBritain)separatedtheyeastjuiceintotwofractions

3、:oneheat-labile,nondialyzablezymase(enzymes)andtheotherheat-stable,dialyzablecozymase(metalions,ATP,ADP,NAD+).（1929NobelPrizelaureate)1910s-1930s,GustavEmbdenandOttoMeyerhof(Germany),studiedmuscleanditsextracts:Reconstructedallthetransformationstepsfromgl

4、ycogentolacticacidinvitro;revealedthatmanyreactionsoflacticacid(muscle)andalcohol(yeast)fermentationswerethesame!GlycolysiswasalsoknownasEmbden-Meyerhofpathway.（1922NobelPrizelaureate)Thewholepathwayofglycolysis(Glucosetopyruvate)waselucidatedbythe1940s.葡

5、萄糖糖酵解的反应过程(Embden-MeyerhofPathway，EMP)丙酮酸甘油醛－3-磷酸前5步，准备阶段，已糖分裂成二个三碳糖，消耗2ATP后5步，贮能阶段，三碳糖氧化，产生2NADH和4ATP糖酵解的全部反应过程在胞浆(cytoplasm)中进行，一分子葡萄糖经无氧酵解可净生成两分子ATP。ATPbindstotheenzymeasacomplexwithMg++.ThefirstprimingreactionTrapsglucoseinsidecellsIrreversible⑴Hexoki

6、nase（己糖激酶）葡萄糖磷酸化生成6-磷酸葡萄糖(G-6-P)1.酵解途径详解（10种酶催化10步反应）HexokinaseGlucoseInducedfitHexokinase（己糖激酶）Glucokinase（葡萄糖激酶）Ubiquitous(普遍存在的)NonspecificProductinhibitionLowKm(0.1mM)LiverSpecificNoproductinhibitionHighKm(10mM)Isozymes(同工酶）（2）PhosphoglucoseIsomerase（

7、磷酸葡萄糖异构酶）G-6-P异构为6-磷酸果糖（fructose-6-phosphate,F-6-P）；AldotoKetoisomerization醛到酮异构化ThesecondprimingreactionIrreversibleRate-limitingstepofGlycolysisPlaysamajorroleintheregulationofglycolysis（3）Phosphofructokinase1(PFK-1,磷酸果糖激酶-1)F-6-P再磷酸化为1,6-双磷酸果糖（F-1,6-BP

8、）CatalyticSite催化位点AllostericSite变构位点ATPHighAffinityATPLowAffinityPhosphofructo-kinase磷酸果糖激酶Onlybindswhenthe[ATP]isveryhigh.Bindsatalow[ATP]Phosphofructokinase1isanallostericenzyme.AllostericallyinhibitedbyATP,citra