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Ch.12 Food as Fuel An Overview of Metabolism
Frost - General, Organic and Biological Chemistry 4th Edition
Frost4th EditionGeneral, Organic and Biological ChemistryISBN: 9780134988696Not the one you use?Change textbook
All textbooksFrost 4th EditionCh.12 Food as Fuel An Overview of MetabolismProblem 92c
Chapter 8, Problem 92c

What metabolic substrate(s) can be produced from the carbon atoms of each of the following amino acids?
c. methionine

Verified step by step guidance
1
Understand that amino acids can be metabolized into various substrates depending on their structure and the metabolic pathways they enter. Methionine is an amino acid that is both glucogenic and ketogenic.
Recognize that methionine is primarily metabolized into succinyl-CoA, which is an intermediate in the citric acid cycle. This makes methionine a glucogenic amino acid because succinyl-CoA can contribute to glucose production via gluconeogenesis.
Note that methionine can also contribute to the production of acetyl-CoA through its metabolism. Acetyl-CoA is a key substrate for the synthesis of ketone bodies, making methionine partially ketogenic.
Consider the biochemical pathway: Methionine is first converted into homocysteine, which can then enter the transsulfuration pathway or be remethylated back to methionine. The transsulfuration pathway leads to the production of succinyl-CoA.
Summarize that the carbon atoms of methionine can be used to produce succinyl-CoA (glucogenic pathway) and acetyl-CoA (ketogenic pathway), depending on the metabolic conditions and the specific pathway utilized.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Amino Acid Metabolism

Amino acid metabolism involves the biochemical processes that break down amino acids for energy or convert them into other compounds. Each amino acid can be transformed into various metabolic substrates, depending on its structure and the body's needs. Understanding these pathways is crucial for determining what substrates can be derived from specific amino acids.
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Methionine Catabolism

Methionine is an essential amino acid that plays a key role in various metabolic pathways, including the synthesis of S-adenosylmethionine (SAMe), a critical methyl donor in numerous methylation reactions. During its catabolism, methionine can be converted into homocysteine and subsequently into other substrates like succinyl-CoA, which can enter the citric acid cycle for energy production.
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Metabolic Substrates

Metabolic substrates are molecules that serve as the starting materials for metabolic reactions, providing the necessary components for energy production and biosynthesis. In the context of amino acids, these substrates can include intermediates that enter pathways like the citric acid cycle or gluconeogenesis, ultimately contributing to the body's energy balance and metabolic functions.
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Related Practice
Textbook Question

In what organ does the urea cycle take place?

Textbook Question

Name the reaction that removes nitrogen from an α-amino acid, forming an α-keto acid.

Textbook Question

How many ATP are produced when glucose is oxidized to pyruvate compared to when glucose is oxidized to CO2 and H2O?

Textbook Question

Consider the complete oxidation of capric acid, a saturated fatty acid, [10:0].

c How many ATP are generated from the complete oxidation of capric acid?

Textbook Question

Consider the complete oxidation of arachidic acid, a saturated fatty acid, [20:0].

b. How many cycles of β oxidation occur?

Textbook Question

Lauric acid, a saturated fatty acid, [12:0], is found in coconut oil.

a. Draw fatty acyl lauric acid activated for β oxidation.