22章-糖酵解作用.ppt

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TheDevelopmentofGlycolysis1897,EduardBuchner(Germany),accidentalobservation:sucrose(asapreservative)wasrapidlyfermentedintoalcoholbycell-freeyeastextract.（1907NobelPrizelaureate)1900s,ArthurHardenandWilliamYoung(GreatBritain)separatedtheyeastjuiceintotwofractions:oneheat-labile,nondialyzablezymase(enzymes)andtheotherheat-stable,dialyzablecozymase(metalions,ATP,ADP,NAD+).（1929NobelPrizelaureate)1910s-1930s,GustavEmbdenandOttoMeyerhof(Germany),studiedmuscleanditsextracts:Reconstructedallthetransformationstepsfromglycogentolacticacidinvitro;revealedthatmanyreactionsoflacticacid(muscle)andalcohol(yeast)fermentationswerethesame!GlycolysiswasalsoknownasEmbden-Meyerhofpathway.（1922NobelPrizelaureate)Thewholepathwayofglycolysis(Glucosetopyruvate)waselucidatedbythe1940s.葡萄糖1.酵解途径详解（10种酶催化10步反应）ATPbindstotheenzymeasacomplexwithMg++.ThefirstprimingreactionTrapsglucoseinsidecellsIrreversible（2）PhosphoglucoseIsomerase（磷酸葡萄糖异构酶）ThepayoffphaseofglycolysisThe“highenergy”acylthioesterisattackedbyPitoyieldtheacyl（酰基）phosphate(~P)product.ThisstepcanbebypassedbyArsenate(砷酸盐，analogoustophosphate).如果葡萄糖的C1,C3,orC6被标记，在厌氧条件下，丙酮酸的哪个C会被标记？3、丙酮酸的去路 1.无氧情况下厌氧发酵生成乳酸(动物）或乙醇（酵母）WhyshouldNAD+berecycled?4、糖酵解途径的调节 1.磷酸果糖激酶（PFK） 是最关键的限速酶，为一别构酶。抑制剂：ATP、柠檬酸、H+激活剂：AMP、F-2,6-BP2.己糖激酶的调节 调节糖酵解的入口。不是关键反应步骤。3.丙酮酸激酶的调节 调节酵解的出口。 +：F-1，6-2P -：ATP、丙氨酸Mostkeyrate-limitingstepofGlycolysisThemostpotentallostericactivatorofPFK-1inliverisfructose-2,6-bisphosphate(F-2,6-BP)HexokinaseHKisallostericallyinhibitedbytheproduct,G-6-PPyruvateKinaseATPandAlanineareallostericinhibitorsF-1,6-2Pisanallostericactivator5、其它单糖进入酵解的途径 1.D-果糖可以通过己糖激酶催化为F-6-P进入酵解还可以通过果糖激酶催化为F-1-P，在醛缩酶的作用下生成磷酸二羟丙酮和甘油醛，前者