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Description of Glycolysis
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Class 19
Glycolysis Read Lehninger 14.1-14.2
pages 528 - 546
Objectives
Describe the importance of glycolysis to living systems Memorize the steps of glycolysis Identify which steps require and input of energy and which produce energy Explain the reaction mechanism of key enzymes Understand the chemical logic of glycolysis
Glyco-lysis: hydrolysis of sugar
Glycolysis
Glucose + 2ADP + 2Pi + 2NAD+ 2pyruvate + 2ATP + 2NADH + 2H+ = 85/
Glucose + 602 6CO2 + 6H2O = 2870/
Glycolysis
Hexokinase
= 16.7/
Phosphohexoseisomerase
= 1.7/
Phosphofructokinase-1
= 14.2/
Aldolase
= 23.8/
Aldolase intermeadiate
Triose phosphate isomerase
Glyceraldehyde-3-phosphate dehydrogenase
Glyceraldehyde-3-phosphate dehydrogenase
Phosphoglycerate kinase
G3P + ADP + Pi + NAD+ 3PG + ATP + NADH + H+ = 12.2/
Phosphoglycerate kinase
Phosphoglycerate mutase
(bisphosphoglycerate mutase)
(2,3-bisphosphoglycerate)
Enolase
Pyruvate kinase
Chemical logic of glycolysis
Chemical logic of glycolysis
Invest energy to split glucose into two high energy compounds Isomerization of glucose to fructose permits equal splitting to two 3-carbon aldehydes Oxidize aldehyde to acid and generate a high-energy, bisphospho compound Extract energy from bisphospho compounds by rearrangement and transfer of phospho groups to ADP
Energetics of glycolysis Enzyme Yield G G [product] uM
Hexokinase -1 ATP -16.7 -33.5 [G6P] 25
Phosphoglucoseisomerase +1.7 -2.5 [F6] 5.4
Phosphofructokinase-1 -1 ATP -14.2 -22.2 [F1,6P] 4.6
Aldolase +23.9 -1.3 [DHAP] 4.9
Triose phosphate isomerase +7.6 0 [G3P] 2.6
Glyceraldehyde-3-phosphate dehydrogenase
+2 NADH +6.3 (+12.6) -1.7 (-3.4) n/d
Phosphoglycerate kinase +2 ATP -18.8 (-37.6) 0 [3PGA] 61.2
Phosphoglycerate mutase +4.4 (+8.8) 0 [2PGA] 4.3
Enolase -3.2 (-6.4) -3.3 (-6.6) [PEP] 8.8
Pyruvate kinase +2 ATP -31.4 (-62.8) -16.7 (-33.4) [Pyr] 73.5
Net +2 ATP +2 NADH
-83.1 -102.9 ATP 1128
Class 19ObjectivesGlyco-lysis: hydrolysis of sugarGlycolysisGlycolysisSlide Number 6HexokinaseSlide Number 8PhosphohexoseisomerasePhosphofructokinase-1AldolaseSlide Number 12Aldolase intermeadiateTriose phosphate isomeraseSlide Number 15Glyceraldehyde-3-phosphate dehydrogenaseSlide Number 17Glyceraldehyde-3-phosphate dehydrogenasePhosphoglycerate kinasePhosphoglycerate kinasePhosphoglycerate mutaseSlide Number 22(bisphosphoglycerate mutase)Slide Number 24(2,3-bisphosphoglycerate)EnolasePyruvate kinaseChemical logic of glycolysisSlide Number 29Chemical logic of glycolysisEnergetics of glycolysis