Given what you know about the involvement of nicotinamide nucleotides inoxidative and reductive metabolic reactions, predict whether the followingintracellular concentration ratios should be 1, > 1, or < 1. Explain youranswers.(a) [NAD+] >[NADH](b) [NADP+] >[NADPH](c) Since NAD+ and NADP+ are essentially equivalent in their tendency to attract electrons, discuss how the two concentration ratios might bemaintained inside cells at greatly differing values.

Given what you know about the involvement of nicotinamide nucleotides inoxidative and reductive metabolic reactions, predict whether the followingintracellular concentration ratios should be 1, > 1, or < 1. Explain youranswers.(a) [NAD+] >[NADH](b) [NADP+] >[NADPH](c) Since NAD+ and NADP+ are essentially equivalent in their tendency to attract electrons, discuss how the two concentration ratios might bemaintained inside cells at greatly differing values.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 4P

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Given what you know about the involvement of nicotinamide nucleotides in oxidative and reductive metabolic reactions, predict whether the following intracellular concentration ratios should be (1) unity, (2) greater than unity, or (3) less than unity. Explain your answers. (a) [NAD*]/[NADH] (b) [NADP*]/[NADPH] Because NAD* and NADP* are essentially equivalent in their ten- dency to attract electrons, discuss how the two concentration ratios might be maintained inside cells at greatly differing values.
(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
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?
(b) the activity of the malate-aspartate shuttle (MAS) system of isolated rat brain mitochondria suspended in an isotonic me- dium buffered to pH 7.4. Diagram A illustrates NADH fluo- rescence emission upon addition of Glutamate in the ab- sence and presence of Aspartate. Diagram B illustrates sim- ilarly NADH fluorescence emission upon addition of Gluta- mate in the presence of Aspartate followed by additions of submicromolar concentrations of Ca2+. As is well estab- lished, the MAS in brain, skeletal muscle, and cardiac mus- Diagrams A and B on the right show changes in Glu A Glu В -No Asp + 0 +0.12 -0.48 + 16 0.81 +1.8 ++ Asp 10 min 2 min cle mitochondria is activated by cytosolic concentrations of Ca2* < 3 µM. To simulate the cytosolic part of the MAS, the following reagents were added to the medium: 4 units/ml glutamate-oxaloacetate transaminase, 6 units/ml malate dehydrogenase, 66 µM NADH, 5 mM aspartate, 5 mM malate, 0.5 mM ADP, 200 nM ruthenium red (to block the mitochondrial…
There is a proposal that pyrazole could protect against the damaging effects of alcohol on the liver that resultfrom prolonged decrease in the ratio of [NAD+]/[NADH] caused by the oxidation of alcohol. ( NAD+ isrequired for several key dehydrogenation steps in the pathway of glucose synthase. NADH promotes theaccumulation of fat in the liver cells) Assuming that pyrazole is not toxic and that it is transported to the liver,evaluate its potential as an antidote to liver damage in treating chronic alcoholism. Would it be a reasonabletherapeutical candidate? Explain. Please explain and please don't copy bartleyby answer.
Imagine a triglyceride comprised of (3) saturated C12 fatty acids. Calculate the number of ATP generated from the complete oxidation of one of these 12-carbon fatty acids to CO2 and water in the liver. Assume that each NADH = 2.5 ATP and each FADH2 = ETC generates 1.5 ATP. Any step that yields pyrophosphate as a product should be treated as an input (i.e. net loss) of (2) ATP.
The enzyme lactate dehydrogenase catalyzes the reversible reaction lactate (CH3 CHOHCOO )+NAD* рyruvate (CH3 COCOO) + NADH + H+ Given the standard reduction potentials CH3 СОСОО + 2H+ + 2е CH3 CHОНСО" E°'= -0. 185 V NADŤ + H+ + 2e- → NADH = -0. 320 V E°' would you expect the reaction to be spontaneous in the forward or reverse direction under biochemical standard state conditions? How could you change the reaction conditions to force the reaction to be spontaneous in the opposite direction? Please explain your answer.
Nicotinamide nucleotide transhydrogenase (NNT) in the inner mitochondrialmembrane catalyzes the reaction NADH + NADP+ → NAD+ + NADPH to generate the NADPH needed for certain reactions that help destroy reactive oxygen species. (a) Explain why the NNT reaction cannot be driven primarily by the diff erence in substrate reduction potentials (Δℰ). (b) In fact, the NNT reaction is driven by proton translocation across the membrane (from outside to inside). How does operation of the transhydrogenase aff ect the effi ciency of oxidative phosphorylation?
For the following enzymes (3-6) predict how the conditions will most likely affect the enzymes activity with one of the following and provide a 1 sentence explanation: a. increase activity b. decrease activity c. not likely to alter activity 3) alpha-ketoglutarate dehydrogenase complex binding to AMP when [AMP] is high. 4) phosphohexose isomerase binding NADH when [NADH] is high 5) phosphofructose-1 binding NAD+ when [NAD+] is high 6) pyruvate dehydrogenase complex binding to ATP when [ATP] is high
In steroid synthesis, squalene is oxidizedto squalene epoxide. This reaction is somewhat unusual, in thatboth a reducing agent (NADPH) and an oxidizing agent (O2) arerequired. Why are both needed?
The conversion of glyceraldehyde-3-phosphate into 1,3-bisphosphoglycerate reduces NAD+ to NADH. Under anaerobic conditions, how is NADH oxidized back to allow for continuing glycolysis? (name the compounds involved in the reaction besides NADH and their draw structures)
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