This has multiple options How does ATP regulate the activity of PFK-1?ATP binds to PFK-1 at the catalytic site as a competitive inhibitor, decreasing PFK-1 activity.ATP binds to the allosteric site as an inhibitor, decreasing PFK-1 activity.ATP binds to the catalytic site as a substrate, increasing PFK-1 activity.ATP binds to the allosteric site as an activator, increasing PFK-1 activity. The graph shows the effect of ATP on the allosteric enzyme phosphofructokinase-1 (PFK-1).PFK-1 activity (% of Vmax)100806040200Low[ADP][ATP]High[ADP]For a given concentration of fructose 6-phosphate, the PFK-1 activity increases with increasing concentrations of ATP, but thereis a point beyond which increasing the concentration of ATP inhibits the enzyme.

Glycolysis is a process in which glucose is oxidized & is converted to pyruvate and in that…

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Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter18: Glycolysis

Section: Chapter Questions

Problem 21P

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Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy charge. a. Would hexokinase be an R enzyme or a U enzyme? Would glutamine: PRPP amidotransferase, the second enzyme in purine biosynthesis, be an R enzyme or a U enzyme? b. If energy charge = 0.5: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low? c. If energy charge = 0.95: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low?
Using the ActiveModel for enoyl-CoA dehydratase, give an example of a case in which conserved residues in slightly different positions can change the catalytic rate of reaction.
Distinguishing the Mechanisms of Class I and Class I Aldolases Fructose bisphosphate aldolase in animal muscle is a class 1 aldolase, which forms a Schiff base intermediate between substrate (for example. fructose-1, 6-bisphosphate or dihydroxyacetone phosphate) and a lysine at the active site (see Figure I8.12). The chemical evidence for this intermediate conies from studies with aldolase and the reducing agent sodium borohydride, NaBH4. Incubation of the enzyme with dihydroxyacetone phosphate and NaBH4 inactivates the enzyme. Interestingly, no inactivation is observed if NabH4 is added to the enzyme in the absence of substrate. Write a mechanism that explains these observations and provides evidence for the formation of a Schiff base intermediate in the aldolase reaction.
Fructose 2,6-bisphosphate is a potent stimulator of phosphofructokinase. Explain how fructose 2,6-bisphosphate might function in the concerted model for allosteric enzymes.
Phosphofructokinase-1 (PFK-1) catalyzes the transfer of a phosphoryl group from ATP to fructose 6-phosphate, Shown is a graph of the rate of PFK-1 vs. [ATP], Concisely explain the shape of the graph. 2 (ATP) (mmol l) PFK-1 reaction rate
In class, I mentioned that fructose is metabolized differently in the liver compared to glucose. Refer to the figure shown below to calculate the number ofATPs you would expect from the metabolism of fructose in the liver. Show your work! Fructokinase Fructose Fructose-1-P АТР ADP Aldolase B Dihydroxy- acetone phosphate Glyceraldehyde АТР Triose kinase Triose phosphate isomerase ADP 4 - Glyceraldehyde-3-P Glycolysis Руruvate Acetyl-CoA Fatty acids and triglycerides
Consider the complete oxidation of one mole of simple TAG containing behenic acid residues (22:0). I. For one mole of the fatty acid residue, determine the following: b. What is the number of ATP yield obtained from NADH coming from the complete β-oxidation of the fatty acid residue
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.
The glucose/glucose-6-phosphate substrate cycle involves distinct reactions of glycolysis and gluconeogenesis that interconvert these two metabolites. Assume that under physiological conditions, [ATP] = [ADP]; [P;] = 1 mM. Consider the glycolytic reaction catalyzed by hexokinase: ATP + glucose ADP + glucose-6-phosphate AG = - 16.7 kJ/mol (a) Calculate the equilibrium constant (K) for this reaction at 298°K, and from that, calculate the maximum [glucose-6-phosphate]/ Iglucose] ratio that would exist under conditions where the reaction is still thermodynamically favorable. (b) Reversal of this interconversion in gluconeogenesis is catalyzed by glucose-6-phosphatase: glucose-6-phosphate + H20 = glucose + P AG" = -13.8 kJ/mol
Intramitochondrial ATP concentrations are about 5 mM, and phosphate concentration is about 10 mM. If ADP is five times more abundant than AMP, calculate the molar concentrations of ADP and AMP at an energy charge of 0.85. Calculate AG for ATP hydrolysis at 37 °C under these condi- tions. The energy charge is the concentration of ATP plus half the concen- tration of ADP divided by the total adenine nucleotide concentration: [ATP] + 1/2[ADP] [ATP] + [ADP] + [AMP]
In working skeletal muscle under anaerobic conditions, glyceraldehyde 3-phosphate is converted to pyruvate (the payoff phase of glycolysis), and the pyruvate is reduced to lactate. Write balanced biochemical equations for all the reactions in this process, with the standard free-energy change for eachreaction. Then write the overall or net equation for the payoff phase of glycolysis (with lactate as the end product), including the net standard free-energy change.
Consider the complete oxidation of one mole of simple TAG containing behenic acid residues (22:0). I. For one mole of the fatty acid residue, determine the following: c. What is the number of ATP yield obtained from FADH2 coming from the complete β-oxidation of the fatty acid residue

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