Standard Reduction Potentials of Some Biologically Important Half-ReactionsHalf-reactionE" (V)Pyruvate- + 2H + 2e → lactate--0.185Acetaldehyde + 2H* + 2e- → ethanol-0.197FAD + 2H+ + 2e → FADH2-0.219aGlutathione + 2H* + 2e- → 2 reduced glutathione-0.23S+ 2H* + 2e → H2S-0.243Lipoic acid + 2H* + 2e- → dihydrolipoic acid-0.29NAD* + H* + 2e → NADH-0.320NADP* + H* + 2e- → NADPH-0.324Acetoacetate + 2H* + 2e- > B-hydroxybutyrate-0.346a-Ketoglutarate + CO2 + 2H* + 2e- → isocitrate-0.382H* + 2e- > H2 (at pH 7)--0.414Ferredoxin (Fe3+) + e- → ferredoxin (Fe2+)-0.432Source: Data mostly from R. A. Loach, in Handbook of Biochemistry and Molecular Biology, 3rd edn (G. D. Fasman, ed.), Physicaland Chemical Data, Vol. 1, p. 122, CRC Press, 1976.This is the value for free FAD; FAD bound to a specific flavoprotein (e.g., succinate dehydrogenase) has a different E" that dependson its protein environment. Calculate the standard free-energy change, deltaGo, for the reaction in which acetaldehyde is reduced by the biological electron carrierNADH in the reaction acetaldehyde + NADH + H* → ethanol + NAD*. Then calculate the actual free-energy change, deltaG, when theacetaldehyde is 1.85 M, the NADH is 1.55 M, the ethanol is 0.10 M and the NAD* is 0.10 M, at 28.22°C and pH = 7. Give the actualfree-energy change in kJ/mol to one decimal place. See Table 13-7b for the E° values.Table 13-7b: Standard Reduction Potentials of Some Biologically Important Half-Reactions (link opens in new page)

Standard free energy of biochemical reaction is related to standard reduction potential ∆Go = -nFEo…

Answered: Calculate the standard free-energy…

Biochemistry

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Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter20: Electron Transport And Oxidative Phosphorylation

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Triose phosphate isomerase In a key reaction of glycolysis, dihydroxyacetone phosphate (DHAP) is isomerized into glyceraldehyde 3-phosphate (G3P) by the action of the enzyme triose phosphate isomerase: CH₂OH C=O CH₂OPO3²- DHAP CHO HC-OH CH₂OPO3²- G3P AG°¹ +7.5 kJ/mol Because AG is positive, the equilibrium lies to the left. (a) Calculate the equilibrium constant for this reaction, assuming a temperature of 37 °C. (b) In the cell, depletion of G3P makes the reaction proceed. What is the value of AG if the concentration of G3P is kept at 1/100 of the value of the concentration of DHAP? C ZOOM +
Chemical labeling of chymotrypsin by the compound tosylphenylalanine chloromethyl ketone (TPCK) modifies the His 57 in the enzyme's active site. The structure of this derivative is shown below. TPCK inactivates the enzyme because the bulky addition prevents it from cleaving nearby covalent bonds. HCI + CH, C-O Chymotrypsin-His 57 TPCK Modified enzyme True O False
During the process of synthesizing palmitate (C16), an acyl ACP __________. For the sake of this question, don’t treat acetyl ACP or malonyl ACP as an acyl ACP; assume the acyl ACP is a product at least 4 carbons long. Choose ALL that apply. (A) can be condensed with malonyl ACP to produce a Cn+2 b-ketoacyl ACP (B) is formed from the reduction of a trans D2-enoyl ACP(C) is a product of acetyl transacylase(D) is reduced by NADPH (E) is a substrate for b-ketoacyl synthase(F) can be condensed with acetyl ACP to produce a Cn+2 b-ketoacyl ACP
In order to function as an oxidative phosphorylation uncoupler (page 648), 2,4-dinitrophenol must act catalytically, not stoichio- metrically. What does this mean? Identify and discuss an important implication of this conclusion.
H. OH co co2 но H co, 1-isopropylmalate 2-isopropylmalate Biosynthesis of leucine involves conversion of 1-isopropyimalate to 2-isopropylmalate (see above). This proceeds in four steps under basic enzymic catalysis via an isolable compound produced in step 2. Write a detailed mechanism for this conversion. Then, draw the intermediate compound) produced in step 2. • You do not have to consider stereochemistry. • Draw uninvolved carboxyl groups in the anionic state, and enolates as carbanions. When needed, abbreviate CoenzymeA-S- as CH3S- In your drawing. aale
19. The AG, the standard free-energy change, for the isomerization of dihydroxyacetone phosphate (DHAP) to glyceraldehyde 3-phosphate (GAP) is +7.55 kJ/mol. The reaction shown below is catalyzed by an enzyme called Triose Phosphate Isomerase (TPI). OH O OH DHAP OH TPI OH M+ OH GAP OH This reaction takes place in glycolysis. At equilibrium, the ratio of GAP to DHAP is 0.0475 at 25°C and pH 7.00. Equilibrium constant, Keq = 0.0475. A) Is the above reaction endergonic or exergonic (going from left to right) under the given experimental conditions? Why? B) Can the above reaction occur spontaneously under the given experimental conditions? Why or why not?
The standard Gibbs (free) energy of reaction (A,Gº') of the following reaction is equal to zero (at 25 °C and pH 7) pyruvate + aspartate Pyruvate, aspartate and L-alanine are mixed each at a concentration of 1 mM, without oxaloacetate. Calculate the molar concentrations of each compound when the reaction reaches equilibrium. oxaloacétate + L-alanine
His388 Glu357 His388 Glu357 Ring opening Proton HO HO abstraction HO но- G6P He NH- NH His388 His388 His388 Glu357 Glu357 Glu357 HO но HO но- но OH cis-enediol F6P Ring closure intermediate OH Describe the mechanism shown above for phosphoglucose isomerase. Describe the chemistry of each step • How the enzyme appears or might facilitate the chemistry How the enzyme increases the reaction rate.
Calculate the standard free energy for creatine-phosphate hydrolysis in a cell where [creatine-P]=3 mM, [creatine]=2 mM, and [Pi]= 12.1 mM. Is the reaction exergonic or endogonic?
Equation for the esterification of glycerol and three ethanoic acids
The equilibrium constant for the hydrolysis of the peptide alanylglycine (Gly-Ala in the reaction from Part B) by a peptidase is K = 9.0 × 10² at 310 K. Calculate AG for this reaction. Express the Gibbs free energy to three significant figures. AG = Submit ΠΑΠΙ ΑΣΦ Request Answer ? kJ/mol Keq [Gly] [Ala] [Gly-Ala]
Looking at the structure of alpha linolenic acid and knowing the electron carriers produced in each round of traditional beta oxidation for saturated fatty acid chains, how many rounds of beta oxidation will have diminished production of electron carriers due to the presence of double bonds?

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