Consider the malate dehydrogenase reaction from the citric acid cycle. Given the listed concentrations, calculate the free energy change for this reaction at energy change for this reaction at 37.0 'C (310 K). AG"' for the reaction is +29.7 kJ/mol. Assume that the reaction occurs at pH 7. [malate] = 1.43 mM [oxaloacetate] = 0.220 mM (NAD*] = 460 mM [NADH] = 180 mM AG : kJ-mol-

Consider the malate dehydrogenase reaction from the citric acid cycle. Given the listed concentrations, calculate the free energy change for this reaction at energy change for this reaction at 37.0 'C (310 K). AG"' for the reaction is +29.7 kJ/mol. Assume that the reaction occurs at pH 7. [malate] = 1.43 mM [oxaloacetate] = 0.220 mM (NAD*] = 460 mM [NADH] = 180 mM AG : kJ-mol-

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter17: Metabolism: An Overview

Section: Chapter Questions

Problem 14P

See similar textbooks

Similar questions

Given the following information, calculate the physiological ΔG of the isocitrate dehydrogenase reaction at 25°C and pH 7.0: [NAD+]/[NADH] = 8, [α-ketoglutarate] = 0.1 mM, and [isocitrate] = 0.02 mM. Assume standard conditions for CO2 (ΔG°′ is given in Table). Is this reaction a likely site for metabolic control?
Calculate the ΔG for Malate dehydrogenase reaction of CAC if the concentration of oxaloacetate is 1x 10-8 M, malate is 0.2 mM, NAD+ is 10 mM and NADH is 0.1 mM in rat liver mitochondria. ΔGo’ for this reaction is 30 kJ/mole. Please write the units of the final answer and the formula you are using to solve. R = 0.008314kJ/K*mol, T = 298K
Compare the delta ΔG0' values for the oxidation of succinate by NAD+ and by FAD. Use the data given in Table 18.1 to find the E0' of the NAD+-NADH and fumarate-succinate couples, and assume that E0' for the FAD – FADH2 redox couple is nearly 0.05 V. Why is FAD rather than NAD+ the electron acceptor in the reaction catalyzed by succinate dehydrogenase?
The standard free energy change for the reaction catalyzed by phosphoglucomutase is -7.1kJ/mol, (a) calculate ΔG at 37°C when the concentration of glucose-1-phosphate is 1-mM and the concentration of glucose-6-phosphate is 25-mM, (b) Is the reaction spontaneous under these conditions?
The complete combustion of palmitate and glucose yields 9781 kJ ∙ mol−1 and 2850 kJ ∙ mol−1 of free energy, respectively. Compare these values to the free energy (as ATP) obtained though catabolism of palmitate and glucose under standard conditions. Which process is more efficient?
The half-reactions involved in the lactate dehydrogenase (LDH) reaction and their standard reduction potentials are (see attached)). Calculate ΔG at pH 7.0 for the LDH-catalyzed reduction of pyruvate under the following conditions: (a) [lactate]/[pyruvate] = 1 and [NAD+]/[NADH] = 1. (b) [lactate]/[pyruvate] = 160 and [NAD+]/[NADH] = 160. (c) [lactate]/[pyruvate] = 1000 and [NAD+]/[NADH] = 1000. (d) Discuss the eff ect of the concentration ratios in Parts a–c on the direction of the reaction.
Consider one of the reactions of the citric acid cycle shown below Malate + NAD+ ⇆ Oxaloacetate + NADH + H+ (malate dehydrogenase) ΔG˚′ = +29.7 kJ/mol. Describe two factors that allow this thermodynamically unfavorable reaction to occur in the direction of malate to oxaloacetate.
Under standard conditions, NADH reoxidation by the electron-transport chain has a free-energy change equal to –220 kJ/mol. With 100% efficiency, how many ATP could be synthesized under standard conditions? What is the "actual" efficiency given these numbers?
One process catalyzed by NADHNADH dehydrogenase is NADH+H^++ubiquinone ↽−−⇀ NAD+ubiquinolNADH+H^++ubiquinone ↽−−⇀⁢ NAD^++ubiquinol The standard reduction potentials for the half‑reactions are given in the table. Oxidant Reductant ?′0 ubiquinone+2H++2e−ubiquinone+2⁢H++2⁢e^− ubiquinolubiquinol 0.045 NAD^++H^++2e−NAD^++H^++2⁢e^− NADHNADH –0.32 Calculate Δ?′0 for the reaction as shown. Δ?′0=____(V) Calculate Δ?′0 . Δ?′0=____(kJ/mol)
The malaria parasite Plasmodium falciparum does not carry out oxidative phosphorylation and therefore does not use the citric acid cycle to generate reduced cofactors. Instead, the parasite converts amino acid–derived α ketoglutarate to succinate. Write an equation for the α-ketoglutarate → succinate conversion that follows (a) the oxidative (clockwise) path of the citric acid cycle or (b) the reductive (counterclockwise) path of the cycle.
Given the following coupled reactions: phosphoenolpyruvate + H2O → pyruvate + Pi ΔG°'= -61.9 kJ/mol ATP + H2O → ADP + Pi ΔG°'= -30.5 kJ/mol write the overall reaction, calculate the ΔG°’, and determine if the reaction is exergonic or endergonic. The overall reaction is ______ + _______ → _______ + _________ The overall ΔG°’ is ________ kJ/mol. Therefore, the reaction is _______(exergonic/endergonic)
Under anaerobic conditions, Escherichia coli synthesizes an NADH-dependent fumarate reductase rather than succinatedehydrogenase, the flavoprotein that oxidizes succinate to fumarate. a) Write an equation for the reaction catalyzed by fumarate reductase.b) NADH produced by the glyceraldehyde-3-phosphate dehydrogenase reaction is re-oxidized by reducing an organicintermediate. Rather than reduce pyruvate to lactate, anaerobic E. coli utilize fumarate reductase. However, underanaerobiosis, the activity of -ketoglutarate dehydrogenase is virtually nonexistent. Show how fumarate is formed, usinga reaction beginning with PEP and including the necessary TCA cycle enzymes.c) What is the metabolic advantage to anaerobic E. coli in using the fumarate reductase pathway rather than lactatedehydrogenase to re-oxidize NADH?