Some bacteria use the citric acid cycle intermediate, a-ketoglutarate, plus acetyl-CoA, as the starting point for lysine biosynthesis. The first part of this biosynthetic pathway uses the same chemical strategy found in the citric acid cycle. Propose a four-step pathway for the conversion of a-ketoglutarate to 2-oxoadipate. Draw the three missing intermediates, and indicate the chemistry involved in each reaction. Include any cofactors that you think might be required for specific steps. CO0- CO0- C=0 CH2 CH, C=0 CH2 ? ? CH, CH, acetyl-CoA HS-COA COO COO a-Ketoglutarate 2-oxoadipate

Some bacteria use the citric acid cycle intermediate, a-ketoglutarate, plus acetyl-CoA, as the starting point for lysine biosynthesis. The first part of this biosynthetic pathway uses the same chemical strategy found in the citric acid cycle. Propose a four-step pathway for the conversion of a-ketoglutarate to 2-oxoadipate. Draw the three missing intermediates, and indicate the chemistry involved in each reaction. Include any cofactors that you think might be required for specific steps. CO0- CO0- C=0 CH2 CH, C=0 CH2 ? ? CH, CH, acetyl-CoA HS-COA COO COO a-Ketoglutarate 2-oxoadipate

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter23: Fatty Acid Catabolism

Section: Chapter Questions

Problem 16P: Extending the Mechanism of Methylmalonyl-CoA Mutase to Similar Reactions Based on the mechanism for...

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Extending the Mechanism of Methylmalonyl-CoA Mutase to Similar Reactions Based on the mechanism for the methylmalonyl-CoA mutase (see problem 14), write reasonable mechanisms for the following reactions shown.
Some bacteria use the citric acid cycle intermediate, a-ketoglutarate, plus acetyl-CoA, as the starting point for lysine biosynthesis. The first part of this biosynthetic pathway uses the same chemical strategy found in the citric acid cycle. Propose a four-step pathway for the conversion of a-ketoglutarate to 2-oxoadipate. Draw the three missing intermediates, and indicate the chemistry involved in each reaction. Include any cofactors that you think might be required for specific steps.
Some bacteria use the citric acid cycle intermediate, α-ketoglutarate, plusacetyl-CoA, as the starting point for lysine biosynthesis. The first partof this biosynthetic pathway uses the same chemical strategy found inthe citric acid cycle. Propose a four-step pathway for the conversion ofα-ketoglutarate to 2-oxoadipate. Draw the three missing intermediates, andindicate the chemistry involved in each reaction. Include any cofactors thatyou think might be required for specific steps.
The archaebacterium Haloarcula marismortui can use acetate (which is converted to acetyl-CoA) as a precursor for carbohydrate synthesis, but it lacks isocitrate lyase and therefore cannot use the glyoxylate pathway. Instead, it converts isocitrate to α-ketoglutarate, which is then converted to the amino acid methylaspartate in two more steps. This five-carbon compound is modifi ed and broken down to release glyoxylate. Describe the three reactions that lead from isocitrate to methylaspartate.
The mechanism for the conversion from alpha kytoglutarate into succinyl CoA by alpha-ketoglutare dehydrogenase is analogous to the pyruvate dehydrogenase mechanism. Draw and show the major intermediates and arrow pushing for the enzyme-catalyze process for the conversion of alpha-ketoglutarate to succinyl CoA. Note: the carbanion of thiamine pyrophosphate nucleophillically attacks C-2 of the alpha-ketoglutarate, i.e., the carbonyl carbon of that substrate.
Show the structure of each intermediate in the conversion of b-hydroxybutyryl-ACP to butyryl-ACP by the fatty acid synthetase complex. Show where cofactors participate. In your first intermediate, circle the carbon atoms derived from malonyl-CoA.
Fatty acids are converted to their coenzyme A esters in a reversible reaction catalyzed by acyl-CoA synthetase: R-COO +ATP +COA R-C-COA +AMP + PPi a) The reaction involves two steps the first of which forms an enzyme-bound intermediate identified as the mixed anhydride of the fatty acid and AMP: R-C-O-P-O-nibose-adenine Write two chemical equations coresponding to the two steps of the reaction catalyzed by the synthetase. b) The acyl-CoA synthetase reaction as written above is readily reversible. How might the reaction be made to favor formation of fatty acyl-CoA? Write within the box. Anything outside the box will not be graded. From the
Synthesis of the activated form of acetate (acetyl-CoA) is carried out in an ATP-dependent process:(a) The ΔG′° for hydrolysis of acetyl-CoA to acetate and CoA is −32.2 kJ/mol and that for hydrolysis of ATP to AMP and PPi is −30.5 kJ/mol. Calculate ΔG′° for the ATPdependent synthesis of acetyl-CoA.(b) Almost all cells contain the enzyme inorganic pyrophosphatase, which catalyzes the hydrolysis of PPi to Pi. What effect does the presence of this enzyme have on the synthesis of acetyl-CoA? Explain.
Behenate (C22H44O2) can be obtained by chain elongation from palmitate. How many ATP equivalents are produced in the degradation of behenate to eleven acetyl-CoA?
2-Bromopalmitoyl-CoA inhibits the oxidation of palmitoyl-CoA by isolated mitochondria but has no effect on the oxidation of palmitoylcarnitine. What is the most likely site of inhibition by 2-bromopalmitoyl-CoA?
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: a. ATP yield obtained from the oxidation of acetyl CoA entering the TCA cycle and ETC b. ATP yield obtained from NADH coming from the complete β-oxidation of the fatty acid residue c. ATP yield obtained from FADH2 coming from the complete β-oxidation of the fatty acid residue
In 1937, two German biochemists published a paper proposing these reactions as part of glucose oxidation: citrate → isocitrate → α-ketoglutarate →succinate → fumarate → malate → oxaloacetate. Adding succinate, fumarate, or malate to thin slices of tissue increased oxygen consumption, supporting the hypothesis that these molecules are intermediates in the process. However, they were puzzled by the observation that these intermediates were still present in the reaction mixture at the end of the experiment. They had thought that intermediates would be consumed as they were converted to the next molecule in the pathway. What explains the observation that these intermediates were still present? a) The pathway is a cycle, constantly regenerating intermediates as glucose is broken down. b) Succinate, fumarate, and malate are not reactants but catalysts, and catalysts are not consumed in the process. c) Succinate, fumarate, and malate increase metabolism and therefore oxygen consumption,…