TThe oxidation of malate by NAD to form oxaloacetate is a highly endergonic reaction under standard conditions.AG° = +29 kJ mol¯¹ (+7 kcal mol¯¹)Malate + NAD+ = oxaloacetate + NADH + H+The reaction proceeds readily under physiological conditions.Why does the reaction proceed readily as written under physiological conditions?Endergonic reactions such as this occur spontaneously without the input of free energy.The steady-state concentrations of the products are low compared with those of the substrates.The reaction is pushed forward by the energetically favorable oxidation of fumarate to malate.O The NADH produced during glycolysis drives the reaction in the direction of malate oxidation.Assuming an [NAD* ]/[NADH] ratio of 8, a temperature of 25°C, and a pH of 7, what is the lowest [malate]/[oxaloacetate] ratioat which oxaloacetate can be formed from malate?[malate][oxaloacetate]=

Standards free energy change calculated at biochemical standards is called biochemical standard free…

Answered: The oxidation of malate by NAD to form…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

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…
When grown anaerobically on glucose, yeast (S. cerevisiae) converts pyruvate to acetaldehyde, then reduces acetaldehyde to Pethanol using electrons from NADH. Write the chemical equation for the reaction that reduces acetaldehyde (CH3CHO) to ethanol (CH3CH2OH). The table provides the standard reduction potential, E', of the relevant half-reactions. Half-reaction Acetaldehyde + 2 H+ + 2e¯ → ethanol NAD+ + 2H+ + 2e¯ → NADH + H+ E'° (V) -.197 -.320 Calculate the equilibrium constant, K'eq, at 25.0 °C for the reaction that reduces acetaldehyde to ethanol. K'e ×10 = eq
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?
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] 1.25 mM [oxaloacetate] = 0.290 mM [NAD+] = 430 mM [NADH] : = 170 mM AG : kJ-mol-1 * TOOLS x10
(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 the maximum concentration of oxaloacetate at which the reaction will still be exergonic. malate + NAD*→ oxaloacetate + NADH + H* lactate + NAD →→ pyruvate + NADH + H+ half reaction Pyruvate + 2H+ + 2e → lactate Pyruvate + CO₂ + H + 2e → malate Intracellular steady state concentrations: malate = 410 μM; NAD = 20.0 mM; pyruvate = 3.22 mM; NADH = 290 μM; AG=+29.7 kJ/mol AG¹ = +25.1 kJ/mol E° (V) - 0.190 - 0.330 lactate 1.1 mM CO₂ = 15.5 torr
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)
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
In the hydrolysis of ATP to ADP and Pi, the equilibrium concentration of ATP is too small to be measured accurately. A better way of determining K’eq, and hence ΔG◦’ of this reaction, is to break it up into two steps whose values of ΔG◦’ can be accurately determined. This has been done using the following pair of reactions (the first being catalyzed by glutamine synthetase): (1) ATP + glutamate + NH3 ⇌ ADP + Pi + glutamine + H+ ΔG1◦’= -16.3 kJ/mol (2) glutamate + NH3 ⇌ glutamine + H2O + H+ ΔG2◦’= 14.2 kJ/mol What is the ΔG◦’ of ATP hydrolysis according to these data and is the overall reaction spontaneous? What is the value of the equilibrium constant for the overall reaction at 25.0 °C. If the concentration of ATP at equilibrium is 20.0 mM and the concentration of ADP at equilibrium is 50 nM. What is the concentration the phosphate group (in mM) at equilibrium?
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
ATP Synthase is known to catalyze the synthesis of ATP with a ΔG°’ close to zero, and a Keq' close to. Why is the value of ΔG°’ different from the known value which is 30.5 kJ/mol (the energy for the reverse of ATP hydrolysis)? If the Keq' value is close to one, how is it ensured that the reaction is driven to the product side and more ATP is obtained?
If a 0.1 M solution of glucose 1- phosphate at 25 °C is incubated with a catalytic amount of phosphoglucomutase, the glucose 1-phosphate is transformed to glucose 6-phosphate. At equilibrium, the concentrations of the reaction components are Calculate Keq and ΔG′° for this reaction.
For an enzyme catalyzed reaction of the form: S + E → P + E, the rate of product formation, [P], is given by: d[P]/dt = k2[E}total [S] /(Km + [S]) = For the enzymatically catalyzed hydrolysis of ATP at 25 °C and pH 7.0, the Michaelis Menten constant, Km was found to be equal to 16.8 μmol L 1 and the value of k2[E]total was found to be 0.220 μmol L-¹s¹. Find the initial rate at an initial ATP concentration of 30.0 μmol L-1

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781305961135

Author:

Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Fundamentals of General, Organic, and Biological …

Biochemistry

ISBN:

9780134015187

Author:

John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson

Publisher:

PEARSON

SEE MORE TEXTBOOKS