Show that the reaction Glucose 2 Glyceraldehyde-3-phosphate is slightly endergonic (G' = 2.2 kJ mol -1

Show that the reaction Glucose → 2 Glyceraldehyde-3-phosphate is slightly endergonic (ΔG°' = 2.2 kJ mol^-1 = 0.53 kcal mol^-1); that is, it is not too far from equilibrium. Use the data in Table 17.1.

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Table 17.1 Step Reaction 1 Glucose + ATP → Glucose-6-phosphate + ADP 2 Glucose-6-phosphate → Fructose-6-phosphate 3 Fructose-6-phosphate + ATP→Fructose-1, 6-bisphosphate + ADP 4 Fructose-1,6-bisphosphate → Dihydroxyacetone phosphate + Glyceraldehyde-3-phosphate 5 Dihydroxyacetone phosphate → Glyceraldehyde- 3-phosphate 6 2(Glyceraldehyde-3-phosphate + NAD+ + P₁ → 1,3-bisphosphoglycerate + NADH + H¹) 7 The Reactions of Glycolysis and Their Standard Free-Energy Changes 8 9 10 Overall 2(1,3-bisphosphoglycerate + ADP → 3-Phosphoglycerate + ATP) 2(3-Phosphoglycerate → 2-Phosphoglycerate) 2(2-Phosphoglycerate → Phosphoenolpyruvate + H₂O) 2(Phosphoenolpyruvate + ADP → Pyruvate + ATP) Glucose + 2ADP + 2P, + NAD+ → 2 Pyruvate → 2ATP + NADH + H+ - 2(Pyruvate + NADH + H+ → Lactate + NAD+) Glucose + 2ADP + 2P;→2 Lactate + 2ATP Enzyme kJ mol-¹ Hexokinase/Glucokinase -16.7 Glucose phosphate isomerase +1.67 Phosphofructokinase -14.2 Aldolase Triose phosphate isomerase Glyceraldehyde-3-P dehydrogenase Phosphoglycerate kinase Phosphoglyceromutase Enolase Pyruvate kinase Lactate dehydrogenase +23.9 AG *** +7.56 kcal mol-¹ -4.0 +0.4 -3.4 2(-18.8) +5.7 +1.8 2(+6.20) 2(+1.5) 2(-4.5) 2(+4.4) 2(+1.8) 2(+0.4) 2(-31.4) 2(-7.5) AG** kJ mol-¹ -33.9 -2.92 -18.8 -73.3 -17.5 2(−25.1) 2(-6.0) -123.5 - 29.5 -0.23 +2.41 2(+1.1) 2(+0.83) 2(+1.1) 2(-1.29) 2(+0.1) 2(-23.0) -98.0 2(-14.8) -127.6