2. Isocitrate dehydrogenase is an enzyme of 2 subunits with two active sites, catalyzing the reaction: COO™ COO™ COO™ COO™ çoo CH₂ CH₂ CH₂ CH₂ HICIC NAD+ H+ NADH CO₂ H* H-C-C H-C-H HO–C—H C=0 Isocitrate Oxalosuccinate a-Ketoglutarate (a). The enzyme is allosteric and is regulated by ADP. Isocitrate and NAD+ bind in the active site. The diagrams to the right illustrate the influence of ADP as an allosteric effector ligand and the influence of NADH on the reaction velocity. Explain the significance of these kinetic observa- tions with respect to the function of the cit- ric acid cycle to keep the respiratory chain of mitochondria supplied with NADH and succinate. Explain why the TCA cycle does not operate when there is no O2 pre- sent in the cell even though no reaction of the TCA cycle directly consumes O2. [Isocitrate] [NADH]- (b)( Calculate the AG for the isocitrate dehydrogenase reaction at 25° C and pH 7 under the following conditions: [NAD+]/[NADH] = 8; [a-ketoglutarate] = 0.1 mM; and [isocitrate] = 0.02 mM. As- sume standard conditions for CO2. On the basis of the result, comment on the need to regulate this reaction in the TCA cycle. For this reaction AG'° = 21 kJ/mol. V +ADP, Km H-C 0.1 mM || C-O.. ار Mn No ADP Km 0.5 mm

2. Isocitrate dehydrogenase is an enzyme of 2 subunits with two active sites, catalyzing the reaction: COO™ COO™ COO™ COO™ çoo CH₂ CH₂ CH₂ CH₂ HICIC NAD+ H+ NADH CO₂ H* H-C-C H-C-H HO–C—H C=0 Isocitrate Oxalosuccinate a-Ketoglutarate (a). The enzyme is allosteric and is regulated by ADP. Isocitrate and NAD+ bind in the active site. The diagrams to the right illustrate the influence of ADP as an allosteric effector ligand and the influence of NADH on the reaction velocity. Explain the significance of these kinetic observa- tions with respect to the function of the cit- ric acid cycle to keep the respiratory chain of mitochondria supplied with NADH and succinate. Explain why the TCA cycle does not operate when there is no O2 pre- sent in the cell even though no reaction of the TCA cycle directly consumes O2. [Isocitrate] [NADH]- (b)( Calculate the AG for the isocitrate dehydrogenase reaction at 25° C and pH 7 under the following conditions: [NAD+]/[NADH] = 8; [a-ketoglutarate] = 0.1 mM; and [isocitrate] = 0.02 mM. As- sume standard conditions for CO2. On the basis of the result, comment on the need to regulate this reaction in the TCA cycle. For this reaction AG'° = 21 kJ/mol. V +ADP, Km H-C 0.1 mM || C-O.. ار Mn No ADP Km 0.5 mm

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter20: Electron Transport And Oxidative Phosphorylation

Section: Chapter Questions

Problem 19P

See similar textbooks

Similar questions

What is the catalytic efficiency of Catalase ? Table. The values of KM and kcat for some Enzymes and Substrates Enzyme Carbonic anhydrase Substrate CO2 HCO3 KM (M) 1.2 x 10-2 2.6 x 10-2 Kcat (s-1) 1.0 x 106 4.0 x 105 Catalase H2O2 2.5 x 10-2 1.0 x 107 Urease Urea 2.5 x 10-2 4.0 x 105 O A. 4 x 108 M-s-1 O B. 4 x 108 M-1.s-1 OC25x 10-9 M-s1 D. 2.5 x 102 M-1.s-1 OE 1.0 x 107 s1
Carbonic anhydrase catalyzes the hydration of CO. CO2 + H2O ¬ H½CO3 The Km of this enzyme for CO, is 1.20×104 µ.M. When [CO,] = 3.60×104 µM, the rate of reaction was 4.50 umol·mL! sec-1 a What is Vmax for this enzyme? umol·mL-!sec-!
Given the conditions below A (Enz A)→ B-(Enz B) C (Enz C) D (Enz D) →E Enzyme Reaction Rate @ Q1o Reaction Rate at 20 C 30 C A 1.38 1.68 1.44 2.78 C 1.23 1.84 1.58 1.96 If tissue D exhibits a reaction rate of 1.58 umol CO2 gFW-1 hr-1 at 20 C and has a Q10 of 1.96, what is the reaction rate at 30 C?
Handwritten Identify the molecule names, enzyme name, enzyme classification and change in reaction(for glycolysis pathway)
enzyme-inhibitor complex requires 450 kJ.mol-1 to dissociate and that it displays kinetics somehow similar to non-competitive inhibition, does this is inhibitor good to use to inhibit toxanthine oxidase in the case of hyperuricemia and gout?
Imagine a typical enzyme kinetic curve of [S] vs. V. The maximum [S] is about four times the Km. Lines are drawn at [S] = Km and V = Vmax. The asymptote is drawn at [S] = 0. 1. What effect does altering Km have on Vmax? Explain. 2. What effect does altering [E] have on Km? Vmax? Explain. 3. At what concentration of [S] is the initial velocity proportional to [E]? Explain.
Use the Michaelis-Menten equation to complete the enzyme kinetic data set, when Km is known to have a value of 1 mmol L-1. [S] (mmol L-1) Vo (umol L-1 min-1) 0.5 50 1.0 2.0 3.0 10.0
Biochemists consider the citric acid cycle to be the cen-tral reaction sequence in metabolism. One of the key steps isan oxidation catalyzed by the enzyme isocitrate dehydrogenaseand the oxidizing agent NAD. Under certain conditions, thereaction in yeast obeys 11th-order kinetics Rate=k[enzyme][isocitrate]⁴[AMP]²[NAD⁺]m[Mg²⁺]² What is the order with respect to NAD⁺?
enzyme-inhibitor complex requires 450 kJ.mol-1 to dissociate and that it displays kinetics somehow similar to non-competitive inhibition, this enzyme is good to use to inhibit toxanthine oxidase in the case of hyperuricemia and gout?
6. Malate dehydrogenase catalyzes the following reversible reaction: COO- HO-C-H CH₂ COO™ L-Malate NAD+ y malate NADH + H+ dehydrogenase COO- 0=C CH₂ COO™ Oxaloacetate AG'° = 29.7 kJ/mol Malate + NAD+→NADH + H+ + oxaloacetate Calculate AG" and the ratio or products and reactants for the malate dehydrogenase reaction to proceed from left to right as shown. (The Faraday constant. 3, is 96.48 kJ/V-mol; RT(37°C)= 2.58kJ/mol) Steps: 1. Explain how you determined which molecule is an electron donor Malate and which is an acceptor NAD*. -2- 2. Calculate AED (write equation, then show calculations, for standard reduction potentials (E_values) see table in the posted lecture) 3. Calculate AG (write equation, then show calculations) 4. Calculate the ratio of products and reactants needed to for Malate + NAD+→→NADH + H+ + oxaloacetate reaction to proceed forward (write equation, then show calculations)
O2 is a competitive inhibitor of the hydrogenase enzyme that catalyzes the conversion between protons & electrons and H2. The inhibition by O2 is irreversible, permanently destroying the enzymatic activity.(a) Describe the relevant reactions that take place when a hydrogenase catalyzes H2 production in the presence of O2.(b) Derive the rate equation for v as a function of [E], [H+] and [O2], assuming that the electron concentration/delivery is not rate-limiting.
Directions: Solve the following problem: The enzyme ẞ-methylaspartase catalyzes the deamination of ẞ-methylaspartate: CH,NH, CH OOC-CH-CH-COOOOC-CH-CH-COO+NH mesaconate Williams and Selbin The effects of hydroxymethylaspartate as an inhibitor for this enzyme was studied. The following data wer Substrate Concentration obtained: Reaction Rate without inhibitor (mM) 1 × 10-4 5 x 10-4 1.5 x 10-3 2.5 x 10-3 5 x 10-3 (mM/s) 0.026 0.092 0.136 0.150 0.165 Reaction Rate with inhibitor (mM/s) 0.010 0.040 0.086 0.120 0.142 Use Lineweaver-Burk plot to determine the KM and Vmax of the enzyme in the absence of inhibitor. Moreover, determine as well whether the inhibitor is competitive or noncompetitive. Show the graphs and calculations below.