Glucose HO-CH, priming ArP Group KH H first OH H OH , ADP transfer H OH Glucose 6-phosphate o-CH2 e Isomerization HO OH y OH H OH Fructose 6-phosphate ①0-CH2O、CH2-OH H HO seco priming(3 ATP Group reaction → ADP transfer OH H Fructose 1, 6-bisphosphate -0-cH0cH2-0- H HO cleavage OH of 6-carbon sugar Aldol OH H hosphate to(4 two 3-carbon sugaI cleavage phosphates Glyceraldehyde 3-phosphate rization ①0-CH2-CH-C Isomer OH H Dihydroxyacetone phosphate ①-OCH2-C-CH2OH 5
Group transfer Isomerization Group transfer Aldol cleavage The preparatory Phase of glycolysis Isomerization
Glyceraldehyde 3-phosphate(2) ①O-CH2-CH-C 2P 2NAD oxidation and phosphorylation Dehydrogenation 2 NADH+H 1,3-Bisphosphoglycerate (2) ①-0-CH2-CH- first ATP. forming reaction 2ADP Group OH ① (substrate-level 2 ATP transfer phosphorylation 3-Phosphoglycerate (2) ①0-CH2-CH OH (8) Group shift 2-Phosphoglycerate(2) CHo-CH-C OH O →2 H2O Dehydration Phosphoenolpyruvate(2) CHa=C-C second ATP. 2ADP forming reaction G (substrate-level roup t 2 ATP phosphorylation) transfer Pyruvate
The payoff phase of glycolysis Dehydrogenation Group transfer Group shift Dehydration Group transfer
3. Ten enzymes catalyze the ten reactions of glycolysis Hexokinase(also glucokinase in liver catalyzes the first phosphorylation reaction on the pathway: Mg2+ATP2, not profound conformational change on the enzyme, he ces a ATP+- is the actual substrate binding of glucose indu reaction is exergonic and thus thermodynamically favorable(under standard conditions! ) D Phosphohexose isomerase(also called phosphoglucose isomerase)catalyzes the isomerization from glucose 6-P to fructose 6-P, converting an aldose to a ketose
3. Ten enzymes catalyze the ten reactions of glycolysis • Hexokinase (also glucokinase in liver) catalyzes the first phosphorylation reaction on the pathway: Mg2+ATP2- , not ATP4- is the actual substrate; binding of glucose induces a profound conformational change on the enzyme; the reaction is exergonic and thus thermodynamically favorable (under standard conditions!). • Phosphohexose isomerase (also called phosphoglucose isomerase) catalyzes the isomerization from glucose 6-P to fructose 6-P, converting an aldose to a ketose
Phosphofructokinase-l(PFK-l,磷酸果糖激酶-1)then catalyzes the second phosphorylation step, converting fructose 6-P to fructose 1, 6-bisphosphate; the overall rate of glycolysis is mainly controlled at this step; PFK-1 is a highly regulatory enzyme; the plant PFK-1 makes use of PPi, instead of ATP at this step Aldolase(醛缩酶), named for the reverse reaction catalyzes the cleavage("lysis")of fructose 1, 6 bisphosphate from the middle c-c bond to form two 3 carbon sugars, dihydroxyacetone phosphate and glyceraldehyde 3-phosphate this is a reversal aldol condensation reaction; thermodynamically very unfavorable under standard conditions
• Phosphofructokinase-1 (PFK-1, 磷酸果糖激酶-1) then catalyzes the second phosphorylation step, converting fructose 6-P to fructose 1,6-bisphosphate; the overall rate of glycolysis is mainly controlled at this step; PFK-1 is a highly regulatory enzyme; the plant PFK-1 makes use of PPi , instead of ATP at this step. • Aldolase (醛缩酶), named for the reverse reaction catalyzes the cleavage (“lysis”) of fructose 1,6- bisphosphate from the middle C-C bond to form two 3- carbon sugars, dihydroxyacetone phosphate and glyceraldehyde 3-phosphate; this is a reversal aldol condensation reaction; thermodynamically very unfavorable under standard conditions
Triose phosphate isomerase(an extremely efficient enzyme) converts dihydroacetone phosphate to glyceraldehyde 3-phosphate; an intramolecular redox reaction(a hydrogen atom is transferred from C-1 to C-3) Glyceraldehyde 3-phosphate dehydrogenase catalyzes first the oxidation and then the phosphorylation of glyceraldehyde 3-P to form glycerate 1, 3-bisphosphate an acyl phosphate(et 磷酸);2 e" are collected by nad+; a thioester(硫酉) intermediate is formed between glyceraldehyde 3-P and an essential Cys residue of the enzyme, Pi is used here for the phosphorolysis(磷酸解作用);the phosphate group linked to the carboxyl group via a anhydride bond has a high transfer potential. D
• Triose phosphate isomerase (an extremely efficient enzyme) converts dihydroacetone phosphate to glyceraldehyde 3-phosphate; an intramolecular redox reaction (a hydrogen atom is transferred from C-1 to C-3). • Glyceraldehyde 3-phosphate dehydrogenase catalyzes first the oxidation and then the phosphorylation of glyceraldehyde 3-P to form glycerate 1,3-bisphosphate, an acyl phosphate (酰基 磷酸); 2e- are collected by NAD+ ; a thioester (硫酯) intermediate is formed between glyceraldehyde 3-P and an essential Cys residue of the enzyme; Pi is used here for the phosphorolysis (磷酸解作用); the phosphate group linked to the carboxyl group via a anhydride bond has a high transfer potential