(a) Consider the oxidation of malate to oxaloacetate by NAD*:malate + NAD+ → oxaloacetate + NADH + H+In yeast mitochondria, where the pH = 8.1, this reaction is exergonic only at low oxaloacetate concentrations.Assuming a pH = 8.1, a temperature of 37 °C, and the steady-state concentrations given below, calculate themaximum concentration of oxaloacetate at which the reaction will still be exergonic.malate + NAD*→ oxaloacetate + NADH + H*lactate + NAD →→ pyruvate + NADH + H+half reactionPyruvate + 2H+ + 2e → lactatePyruvate + CO₂ + H + 2e → malateIntracellular steady state concentrations:malate = 410 μM;NAD = 20.0 mM;pyruvate = 3.22 mM;NADH = 290 μM;AG=+29.7 kJ/molAG¹ = +25.1 kJ/molE° (V)- 0.190- 0.330lactate 1.1 mMCO₂ = 15.5 torr

Equation for change in Gibbs free energy (∆G) is given below. ∆G=∆G0' + 2.303RT…

Answered: (a) Consider the oxidation of malate to…

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter25: Nitrogen Acquisition And Amino Acid Metabolism

Section: Chapter Questions

Problem 22P

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?
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.
The standard reduction potential for ubiquione (A or coenzyme Q) is .045 V, and the standard reduciton potential (E) for FAD is -0.219 V. Using these values, show that the oxidation for FADH2 by ubiquinone theoretically liberates enough energy to drive the synthesis of ATP. Faraday constant =96.48KJ/Vol delta G' standard for ATP Synthesis is +30.5 KJ/mol R=8.314 J/mol K=1.987 cal/mol K
Consider the two half-reactions below and their standard reduction potentials. NAD+ + H+ + 2e → NADH Elo= -0.32 V a-Ketoglutarate + CO₂ + 2H+ + 2e → Isocitrate E' = -0.38 V (a) What is AE" for the spontaneous redox reaction that is, the reaction that actually occurs under standard biochemical conditions (pH 7)? (b) Which of the following statements are correct under standard biochemical conditions? i. The concentration of H+ is 1.0 M. ii. The reaction NAD+ + Isocitrate → NADH + H+ + a-Ketoglutarate + CO₂ is favor- able. iii. NAD+ accepts electrons from isocitrate. iv. The NAD → NADH reaction actually occurs in reverse. The a-ketoglutarate → isocitrate reaction occurs as written. (c) Calculate AG" for the reaction in (a). (pH 7, 25°C, pressure, 1 atm.) (d) Suppose that the actual conditions are T = 25°C, pH = 7, CO₂ = 1 atm, [a-Ketoglutarate] 10 mM, [NAD+] = 2.5 mM, and [NADH] = 0.5 mM. PAR = 2 mM, [Isocitrate] DE What is the value of AG under those conditions? (Hints: pH 7 is already…
The phosphorylation and oxidative decarboxylation of oxaloacetate by inorganic phosphate (Pi) to make phosphoenolpyruvate and carbon dioxide is endergonic under intracellular conditions. It is characterized by this equation: Oxaloacetate + Pi ←→ Phosphoenolpyruvate + H2O + CO2 ΔG’ = +24.6 kJ/mol The synthesis of GTP from GDP and inorganic phosphate (Pi) in solution is endergonic under intracellular conditions, and it is characterized by this equation: GDP + Pi ←→ GTP + H2O ΔG’ = +30.5 kJ/mol Write a new net thermodynamically coupled reaction equation that describes the synthesis of phosphoenolpyruvate from oxaloacetate using the hydrolysis of GTP to power the reaction and calculate the new net ΔG’ of this reaction. Show all of your work.
Begining with 1 M concentrations of each reactant and product at pH=7 and 25.0 degrees C, calculate the K'eq of the reaction Pyruvate + NADH Lactate + NADH+H+. Note the temperature of this reaction will not affect the standard reducton potential delta E° in the table 13-7b.
Calculate the standard free-energy change of the reaction catalyzed by theenzyme phosphoglucomutase, given that, starting with 20 mM glucose 1-phosphate and no glucose 6- phosphate, the final equilibrium mixture at 25 °C and pH 7.0 contains 1.0 mM glucose 1-phosphate and 19 mM glucose 6-phosphate. Does the reaction in the direction of glucose 6-phosphate formation proceed with a loss or a gain of free energy?
Begining with 1 M concentrations of each reactant and product at pH=7 and 25.0 degrees C, calculate the K'eq (to one decimal point) of the reaction Pyruvate + NADH+H+ <=> Lactate + NAD+.Note the temperature of this reaction will not affect the standard reducton potential delta E'o in the table 13-7b. please provide a comprehensive explanation with each step taken.
The reaction catalyzed by malate dehydrogenase has a ΔG°′ value of +29.7 kJ⋅mol−1. Given what this says about the occurrence of the reaction catalyzed by malate dehydrogenase in cells explain how the reaction catalyzed by citrate synthase (−31.5 kJ⋅mol−1) influences that activity of malate dehydrogenase. In addition, explain how the activity of citrate synthase functions as a regulatory point for the citric acid cycle
Begining with 1 M concentrations of each reactant and product at pH=7 and 25.0 degrees C, calculate the K'eq of the reaction Pyruvate + NADH <=> Lactate + NADH+H+.Note the temperature of this reaction will not affect the standard reducton potential delta E'o in the table 13-7b.
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] = 1.45 mM AG: [oxaloacetate] = 0.130 mM [NAD+ ] = 110 mM [NADH] = 44 mM 47.06 Incorrect kJ.mol-1
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)

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

SEE MORE TEXTBOOKS