Can you answer this? I got it wrong. Coupling ATP hydrolysis to glucose phosphorylation makes thermodynamic sense, but consider how the coupling mighttake place.Given that coupling requires a common intermediate, one conceivable mechanism is to use ATP hydrolysis to raise theintracellular concentration of P₁. The increase in P; concentration would drive the unfavorable phosphorylation of glucose by Pi.Is increasing the P; concentration a reasonable way to couple ATP hydrolysis and glucose phosphorylation?Yes. The extra ATP hydrolysis would provide enough free energy to drive the phosphorylation reaction.No. The extra P; would give a negative AG, but would give a positive AG.No. The phosphate salts of divalent cations would be present in excess and precipitate out.Yes. Increasing the concentration of P; would decrease K'eq and shift equilibrium to the right.

The two individual reactions i.e. glucose phosphorylation and ATP hydrolysis is given below, along…

Answered: Coupling ATP hydrolysis to glucose…

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

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Coupled reactions occur where a nonspontaneous reaction is enabled by coupling it to a spontaneous reaction. This approach is common in biological settings. Determine if ATP could be generated by this biochemical reaction. You have calculated that cell potential is +0.637V. An example of a coupled reaction is the first step of glycolysis, the phosphorylation of glucose to form glucose-6-phosphate shown below. The net ∆Gº for this reaction is
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?
A direct measurement of the standard free-energy change associated with the hydrolysis of ATP is technically demanding because the minute amount of ATP remaining at equilibrium is difficult to measure accurately. The value of ΔG′° can be calculated indirectly, however, from theequilibrium constants of two other enzymatic reactions having less favorable equilibrium constants:Using this information for equilibrium constants determined at 25 °C, calculate the standard free energy of hydrolysis of ATP.
Coupled reactions occur where a nonspontaneous reaction is enabled by coupling it to a spontaneous reaction. This approach is common in biological settings. Determine if ATP could be generated by this biochemical reaction. You have calculated that cell potential is +0.637V. An example of a coupled reaction is the first step of glycolysis, the phosphorylation of glucose to form glucose-6-phosphate shown below. kJ/mol The net AG° for this reaction is 1 2 3 н он H. H- H- H H H H 4 6. H. glucose phosphate anion glucose-6-phosphate AG = +14.0 kJ/mol 7 8 9. АТР ADP phosphate anion AG = -30.5 kJ/mol +/- LO
Consider the following list of phosphorylated compounds with their free energy changes of phosphate hydrolysis: Glucose-1-phosphate (-5.0 kcal/mol), PEP (-14.8 kcal/mole), 1,3-bisphosphoglycerate (-11.8 kcal/mole) and Glucose-6-Phosphate (-3.3 kcal/mol). Given that the free energy change of ATP hydrolysis is -7.3 kcal/mole, which of these molecules be directly synthesized by the transfer of a phospho- group from ATP? 1,3-bisphosphoglycerate Glucose-6-phosphate All of those phosphorylated compounds. PEP Glucose-1-phosphate
UDP-glucose pyrophosphorylase catalyzes the removal of a pyrophosphate group from UTP as it synthesizes UDP-glucose. Why is this necessary, from a biochemical perspective? Both of the phosphate groups from UTP are needed to form UDP-glucose. There is no particular reason: wasteful reactions just happen sometimes. The pyrophosphate (after hydrolysis) is required to free up more phosphate for the synthesis of ATP by oxidative phosphorylation. The subsequent hydrolysis of pyrophosphate is a highly exergonic reaction, which pulls the equilibrium over towards UDP-glucose. Pyrophosphate is an allosteric activator of glycogen synthase, so this helps glycogen synthesis to proceed at a faster rate.
. Because of the position of arsenic in the periodic table, arsenate (AsO}-) is chemically similar to inorganic phosphate and is used by phosphate-requiring enzymes as an alternative substrate. However, organic arsenates are quite unstable and spontaneously hydrolyze. Arsenate is known to inhibit ATP production in glycolysis. Identify the target enzyme, and explain the mechanism of inhibition.
The protein catalase catalyzes the reaction 2H,O,(aq) — 2H,O(l) + O,(g) and has a Michaelis-Menten constant of KM = 25 mM and a turnover number of 4.0 × 107 s¯¹. The total enzyme concentration is 0.010 µM and the initial substrate concentration is 4.83 µM. Catalase has a single active site. Calculate the value of Rmax (often written as Vmax) for this enzyme. Rmax Calculate the initial rate, R (often written as V), of this reaction. R = ×10 mM.s-1 mM-s-1
Decylic acid is a saturated fatty acid that occurs naturally in coconut oil and palm kernel oil. Calculate the net ATP yield when decylic acid undergoes complete B oxidation. The formula of decylic acid is shown below: (Given: The oxidation of one NADH yields 2.5 ATP; the oxidation of one FADH2 yields 1.5 ATP; and the oxidation of one acetyl CoA yields 10 ATP.) O 50 ATP O 52 ATP 66 ATP OH O 64 ATP
Enzymes normally enhance the rates of biochemical reactions by preferentially binding and stabilizing the transition states rather than either the substrates or the products of a reaction. The F|-subunit of ATP synthase does not fit this norm so well as tight binding to ATP rather than a transition state is employed to make ATP. Explain the binding-change model of the mechanism of ATP-synthase. How and why is the proton-motive force used in the reaction cycle of ATP synthase?
A solution of the enzyme hexokinase incubated at 45 °C lost 50% of its activity in 12 min, but when incubated at 45 °C in the presence of a very large concentration of one of its substrates, it lost only 3% of its activity in 12 min. Suggest why thermal denaturation of hexokinase was retarded in the presence of one of its substrates. It is impossible for this result to be true. OA. Adding the substrate increases the weak forces that stabilize the enzyme. OB. The high concentration of substrate forms a barrier around the hexokinase. D. Adding the substrate results in protective covalent bonding.
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?

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