The inhibition of PFK-1 by ATP diminishes when the ADP concentration is high, as shown in the graph.What explains this observation?ADP levels regulate the association of the individual PFK-1 monomers.The [ATP]/[ADP] ratio regulates PFK-1 activity.ADP outcompetes ATP as a phosphoryl donor for PFK-1 at high concentrations.Binding of ADP to the catalytic site increases 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.

PFk-1 is an enzyme involved in glycolysis. It catalyzes the conversion of fructise-6-phoaphate to…

Answered: The inhibition of PFK-1 by ATP…

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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Substrate level phosphorylation is the spontaneous transfer of phosphate from an organic substrate to ADP. These organic substrates have a [more/less/equivalent] negative free energy of hydrolysis than ATP. In glycolysis, 4 total ATP are produced in this way from a single molecule of glucose in [1/2/4] different enzymatic reactions/steps in the [investment/payoff] phase. please help with the ones in []
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.
What would be the metabolic consequences and symptoms of having a mutated form of phosphofructokinase-1 in muscle that is no longer allosterically regulated by [H+]? Speculate on how a patient with this mutation could deal with this.
Carbon monoxide is considered toxic because it acts on Complex IV. How would the addition of carbon monoxide to actively respiring mitochondria affect the relative oxidation-reduction states of all components of the electron-transport chain? Complexes I and I would be reduced, but complexes II and IV would be oxidized because the electrons come from FADH2 oxidation, not NADH. O All four complexes would remain oxidized because they function as a multisystem complex. O Complexes I, II, and I would be reduced and Complex IV would be oxidized. All four complexes would remain reduced because they function as a multisystem complex Complexes I, II, and ill would be oxidized but Complex IV would remain reduced.
For each of the following proteins describe how the protein function would be altered (or not) in the following scenarios: A receptor tyrosine kinase that always dimerizes even in the absence of ligand 3-ketoacyl-CoA transferase (SCOT) that is expressed in the liver. CPT1 that doesn’t have a malonyl binding site 4. acylCoA dehydrogenase with complex V inhibited
Mutations in adenylate kinase have led to a hyperactive enzyme that ultimately ends up elevating ADP levels in a cell.Calculate the EC (energy charge) given the following atypical adenylate concentrations for the cell containing the mutant adenylate kinase: ATP = 0.5 ??��, ADP = 12.2 ??��, AMP = 80 ??��.
Strategies for regulating the central pathways in carbohydrate metabolism vary among different cells in one organism and among organisms. Slight changes in the regulation of enzymes in central metabolism can effectively re-route metabolite traffic through these pathways, just like a small mutation in PFK-1 can convert a healthy cell into a cancerous one. For instance, Gillaspera mold uses an alternative strategy for regulation the TCA and glycolysis. Gillaspera contains a unique isocitrate dehydrogenase that has an allosteric site for citrate. High citrate inhibits isocitrate dehydrogenase in this organism. Gillaspera also lacks a citrate binding site on PFK-1, so this variant of the enzyme is not affected by citrate concentrations at all. Gillaspera lacks the enzymes ethanol dehydrogenase and lactate dehydrogenase and no carbons are lost in its unique fermentation product. Would high glucose in these organisms lead to production of carbon dioxide from glucose catabolism?…
The Beutler test is used to diagnose GALT (UDP-glucose uridyltransferase) deficiency in infants. Blood from the heel is spotted onto filter paper and the spot is then subjected to an enzyme assay. Galactose 1-phosphate, NADP+ and UDP-glucose are added as substrates to the dried blood. The increase in absorbance at 340nm is measured over time which corresponds to reduction of NADP+ to NADPH . The amount of GALT activity in the blood of patients is therefore measured by stoichiometric relationship to the amount of NADPH produced from NADP+. However, GALT does not directly reduce NADP+ as you can see in the above diagram. Instead, the glucose 1-phosphate product from this reaction is shuttled into the oxidative phase of the pentose phosphate pathway by enzymes also present in RBCs. Which three (or possibly more if you must) enzymes downstream of GALT allow for quantitative correlation of a product of GALT with the appearance of NADPH? What is the stoichiometric relationship…
V-class proton pumps run backward relative to the F-class ATP synthase. Consider the cartoon, which shows the conformations of the beta-subunits and ATPIADP + Pj of the F-class synthase. Which of the following associations between the conformation of the beta subunit and ATP/ADP + P¡ is correct for V- Binding Change Mechanism loose binding ADP+P ATP ATP class pumps? C repeat ADP + P, ADP АТР tight binding АТР +P оpen АТР O The open conformation releases ATP. Hydrolysis of ATP to ADP + P¡ drives the change from tight to loose. O Binding of ADP + P¡ drives change from open to loose. Hydrolysis of ATP to ADP + Pj drives the change from open to loose.
The pyruvate dehydrogenase complex catalyzes the synthesis of acetyl-CoA, a very important molecule in cellular metabolism. The reaction catalyzed by the pyruvate dehydrogenase enzyme complex is shown below. This reaction is tightly regulated, because it is essentially irreversible. Which of the following conditions is most likely to lead to the inhibition of pyruvate dehydrogenase in cells? (select two answers) High concentrations of acetyl-CoA High concentrations of pyruvate High concentrations of NADH High concentrations of NAD+ High concentrations of CoA
Sketch the arrow pushing mechanism of the hydrolysis of phospho-serine by the emzyme phosphatase. The enzyme has a catalytic diad. Cys (pka 8.2) and glu (pka 4.3)
Why does FAHD2 oxidation give 1.5 ATP while NADH oxidation gives 2.5 ATP? Explain this in relation to ETC.

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