TABLE 17.1 The Reactions of Glycolysis and Their Standard Free-Energy Changes AG* AG** Step k) mol- kcal mol- kJ mol- Reaction Enzyme 1 Glucose + ATP → Glucose-6-phosphate + ADP Hexokinase/Glucokinase -16.7 -4.0 -33,9 Glucose-6-phosphate → Fructose-6-phosphate Glucose phosphate isomerase +1.67 +0.4 -2.92 -3.4 Fructose-6-phosphate + ATP → Fructose-1, 6-bisphosphate + ADP Phosphofructokinase -14.2 -18.8 4 +5.7 Fructose-1,6-bisphosphate → Dihydroxyacetone phosphate + Glyceraldehyde-3-phosphate Aldolase +23.9 -0.23 +7.56 Dihydroxyacetone phosphate → Glyceraldehyde- 3-phosphate Triose phosphate isomerase +1.8 +2.41 2(Glyceraldehyde-3-phosphate + NAD* + P, → 1,3-bisphosphoglycerate + NADH + H*) 2(-1.29) Glyceraldehyde-3-P dehydrogenase 2(+6.20) 2(+1.5) 7 2(+0.1) 2(1,3-bisphosphoglycerate + ADP → 3-Phosphoglycerate + ATP) Phosphoglycerate kinase 2(-18.8) 2(-4.5) 2(3-Phosphoglycerate → 2-Phosphoglycerate) Phosphoglyceromutase 2(+4.4) 2(+1.1) 2(+0.83) 2(2-Phosphoglycerate → Phosphoenolpyruvate + H,O) Enolase 2(+1.8) 2(+0.4) 2(+1.1) 10 2(Phosphoenolpyruvate + ADP → Ругuvate + ATP) Pyruvate kinase 2(-31.4) 2(-7.5) 2(-23.0) -73.3 2(-25.1) Overall -17.5 Glucose + 2ADP + 2P, + NAD+ → 2 Pyruvate 2ATP + NADH + H* 2(Pyruvate + NADH + H* →Lactate + NAD*) Glucose + 2ADP + 2P, →2 Lactate + 2ATP Lactate dehydrogenase -98.0 2(-6.0) -29.5 2(-14.8) -127.6 -123.5 AG" values are assumed to be the same at 25°Cand 37°C and are calculated for standard-state conditions (1 Mconcentration of reactants and products pH 7.0). AG values are calculated at 310 K (37°C) using steady-state concentrations of these metabolites found in erythrocytes.
TABLE 17.1 The Reactions of Glycolysis and Their Standard Free-Energy Changes AG* AG** Step k) mol- kcal mol- kJ mol- Reaction Enzyme 1 Glucose + ATP → Glucose-6-phosphate + ADP Hexokinase/Glucokinase -16.7 -4.0 -33,9 Glucose-6-phosphate → Fructose-6-phosphate Glucose phosphate isomerase +1.67 +0.4 -2.92 -3.4 Fructose-6-phosphate + ATP → Fructose-1, 6-bisphosphate + ADP Phosphofructokinase -14.2 -18.8 4 +5.7 Fructose-1,6-bisphosphate → Dihydroxyacetone phosphate + Glyceraldehyde-3-phosphate Aldolase +23.9 -0.23 +7.56 Dihydroxyacetone phosphate → Glyceraldehyde- 3-phosphate Triose phosphate isomerase +1.8 +2.41 2(Glyceraldehyde-3-phosphate + NAD* + P, → 1,3-bisphosphoglycerate + NADH + H*) 2(-1.29) Glyceraldehyde-3-P dehydrogenase 2(+6.20) 2(+1.5) 7 2(+0.1) 2(1,3-bisphosphoglycerate + ADP → 3-Phosphoglycerate + ATP) Phosphoglycerate kinase 2(-18.8) 2(-4.5) 2(3-Phosphoglycerate → 2-Phosphoglycerate) Phosphoglyceromutase 2(+4.4) 2(+1.1) 2(+0.83) 2(2-Phosphoglycerate → Phosphoenolpyruvate + H,O) Enolase 2(+1.8) 2(+0.4) 2(+1.1) 10 2(Phosphoenolpyruvate + ADP → Ругuvate + ATP) Pyruvate kinase 2(-31.4) 2(-7.5) 2(-23.0) -73.3 2(-25.1) Overall -17.5 Glucose + 2ADP + 2P, + NAD+ → 2 Pyruvate 2ATP + NADH + H* 2(Pyruvate + NADH + H* →Lactate + NAD*) Glucose + 2ADP + 2P, →2 Lactate + 2ATP Lactate dehydrogenase -98.0 2(-6.0) -29.5 2(-14.8) -127.6 -123.5 AG" values are assumed to be the same at 25°Cand 37°C and are calculated for standard-state conditions (1 Mconcentration of reactants and products pH 7.0). AG values are calculated at 310 K (37°C) using steady-state concentrations of these metabolites found in erythrocytes.
Biochemistry
6th Edition
ISBN:9781305577206
Author:Reginald H. Garrett, Charles M. Grisham
Publisher:Reginald H. Garrett, Charles M. Grisham
Chapter27: Metabolic Integration And Organ Specialization
Section: Chapter Questions
Problem 20P: Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy...
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According to Table 17.1, four reactions have positive ΔG values. How can this be explained?
Transcribed Image Text:TABLE 17.1
The Reactions of Glycolysis and Their Standard Free-Energy Changes
AG*
AG**
Step
k) mol-
kcal mol- kJ mol-
Reaction
Enzyme
1
Glucose + ATP → Glucose-6-phosphate + ADP
Hexokinase/Glucokinase
-16.7
-4.0
-33,9
Glucose-6-phosphate → Fructose-6-phosphate
Glucose phosphate isomerase
+1.67
+0.4
-2.92
-3.4
Fructose-6-phosphate + ATP → Fructose-1,
6-bisphosphate + ADP
Phosphofructokinase
-14.2
-18.8
4
+5.7
Fructose-1,6-bisphosphate → Dihydroxyacetone
phosphate + Glyceraldehyde-3-phosphate
Aldolase
+23.9
-0.23
+7.56
Dihydroxyacetone phosphate → Glyceraldehyde-
3-phosphate
Triose phosphate isomerase
+1.8
+2.41
2(Glyceraldehyde-3-phosphate + NAD* + P, →
1,3-bisphosphoglycerate + NADH + H*)
2(-1.29)
Glyceraldehyde-3-P
dehydrogenase
2(+6.20)
2(+1.5)
7
2(+0.1)
2(1,3-bisphosphoglycerate + ADP →
3-Phosphoglycerate + ATP)
Phosphoglycerate kinase
2(-18.8)
2(-4.5)
2(3-Phosphoglycerate → 2-Phosphoglycerate)
Phosphoglyceromutase
2(+4.4)
2(+1.1)
2(+0.83)
2(2-Phosphoglycerate →
Phosphoenolpyruvate + H,O)
Enolase
2(+1.8)
2(+0.4)
2(+1.1)
10
2(Phosphoenolpyruvate + ADP →
Ругuvate + ATP)
Pyruvate kinase
2(-31.4)
2(-7.5)
2(-23.0)
-73.3
2(-25.1)
Overall
-17.5
Glucose + 2ADP + 2P, + NAD+ →
2 Pyruvate 2ATP + NADH + H*
2(Pyruvate + NADH + H* →Lactate + NAD*)
Glucose + 2ADP + 2P, →2 Lactate + 2ATP
Lactate dehydrogenase
-98.0
2(-6.0)
-29.5
2(-14.8)
-127.6
-123.5
AG" values are assumed to be the same at 25°Cand 37°C and are calculated for standard-state conditions (1 Mconcentration of reactants and products pH 7.0).
AG values are calculated at 310 K (37°C) using steady-state concentrations of these metabolites found in erythrocytes.
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