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Questions and Answers
What is the primary process involved in the first step of amino acid catabolism?
What is the primary process involved in the first step of amino acid catabolism?
Transamination reactions involve the transfer of an amino group from an a-keto acid to an amino acid.
Transamination reactions involve the transfer of an amino group from an a-keto acid to an amino acid.
False
What is the name of the coenzyme that aminotransferases typically require to function?
What is the name of the coenzyme that aminotransferases typically require to function?
pyridoxal phosphate (PLP)
Aminotransferases catalyze transamination reactions and are also known as ______.
Aminotransferases catalyze transamination reactions and are also known as ______.
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Match the following aminotransferases with their action:
Match the following aminotransferases with their action:
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What two compounds play central roles due to their ability to readily transfer and accept amino groups?
What two compounds play central roles due to their ability to readily transfer and accept amino groups?
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Transamination reactions are irreversible.
Transamination reactions are irreversible.
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What is the a-keto acid formed when alanine loses an amino group?
What is the a-keto acid formed when alanine loses an amino group?
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The a-keto acid that gains an amino group in a transamination reaction becomes a(n) ______.
The a-keto acid that gains an amino group in a transamination reaction becomes a(n) ______.
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Which of the following is NOT an example of an aminotransferase?
Which of the following is NOT an example of an aminotransferase?
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What is a common function of amino acid transamination in the body?
What is a common function of amino acid transamination in the body?
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Aminotransferases can catalyze reactions that are irreversible.
Aminotransferases can catalyze reactions that are irreversible.
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What key vitamin is required by aminotransferases in its coenzyme form?
What key vitamin is required by aminotransferases in its coenzyme form?
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The amino acid that loses its amino group in a transamination reaction becomes a(n) ______.
The amino acid that loses its amino group in a transamination reaction becomes a(n) ______.
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Match the following aminotransferases with their corresponding substrates:
Match the following aminotransferases with their corresponding substrates:
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Which of the following amino acids is directly involved in transamination reactions catalyzed by ALT?
Which of the following amino acids is directly involved in transamination reactions catalyzed by ALT?
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The process of transferring an amino group to an a-keto acid is called ______.
The process of transferring an amino group to an a-keto acid is called ______.
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Name one example of an aminotransferase.
Name one example of an aminotransferase.
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Glutamate can readily donate or accept amino groups in amino acid metabolism.
Glutamate can readily donate or accept amino groups in amino acid metabolism.
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Which of the following pairs correctly associates an amino acid with its corresponding a-keto acid?
Which of the following pairs correctly associates an amino acid with its corresponding a-keto acid?
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Which of the following best describes the function of aminotransferases?
Which of the following best describes the function of aminotransferases?
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Pyridoxal phosphate is a coenzyme form of vitamin B12 that is required by aminotransferases.
Pyridoxal phosphate is a coenzyme form of vitamin B12 that is required by aminotransferases.
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The a-keto acid of alanine is known as _________.
The a-keto acid of alanine is known as _________.
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Which of the following enzyme transfers amino groups from aspartate to a-ketoglutarate?
Which of the following enzyme transfers amino groups from aspartate to a-ketoglutarate?
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What two products result from the transamination of alanine using a-ketoglutarate as the a-keto acid?
What two products result from the transamination of alanine using a-ketoglutarate as the a-keto acid?
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The reaction catalyzed by alanine aminotransferase (ALT) is irreversible.
The reaction catalyzed by alanine aminotransferase (ALT) is irreversible.
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Match the following enzymes with their primary substrates in transamination:
Match the following enzymes with their primary substrates in transamination:
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Which a-keto acid is formed when aspartate loses its amino group in a transamination reaction?
Which a-keto acid is formed when aspartate loses its amino group in a transamination reaction?
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The coenzyme form of vitamin B6 required by aminotransferases is called __________.
The coenzyme form of vitamin B6 required by aminotransferases is called __________.
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What role do glutamate and a-ketoglutarate play in amino acid metabolism?
What role do glutamate and a-ketoglutarate play in amino acid metabolism?
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Study Notes
Transamination of Amino Acids
- Transamination is a crucial initial step in breaking down amino acids (catabolism). It frequently (but not always) involves transferring an amino group.
- The process occurs by transamination and/or deamination.
- It involves transferring an amino group from one amino acid to an α-keto acid (also called an amino acid carbon skeleton).
- The carbon skeleton/α-keto acid gaining the amino group becomes an amino acid, and the amino acid losing its amino group becomes an α-keto acid.
- This is important for synthesizing many dispensable amino acids.
- Transamination is catalyzed by enzymes called aminotransferases or transaminases.
- Pyridoxal phosphate (PLP), a form of vitamin B6, is often a necessary coenzyme for these enzymes.
- Examples include tyrosine aminotransferase, branched-chain aminotransferases, alanine aminotransferase (ALT), and aspartate aminotransferase (AST).
- ALT and AST are highly active enzymes in the body.
- ALT facilitates the transfer of amino groups from alanine to α-ketoglutarate, yielding pyruvate and glutamate.
- AST transfers amino groups from aspartate to α-ketoglutarate, forming oxaloacetate and glutamate.
- Both reactions are reversible.
- Glutamate and α-ketoglutarate readily accept and donate amino groups, making them central to amino acid metabolism.
- ALT was formerly called glutamate pyruvate transaminase (GPT).
- AST was formerly called glutamate oxaloacetate transaminase (GOT).
- ALT and AST reactions involve alanine, pyruvate, glutamate, α-ketoglutarate, aspartate, and oxaloacetate.
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Description
Test your knowledge on the transamination process, a vital step in amino acid catabolism. This quiz covers the role of aminotransferases, the involvement of pyridoxal phosphate, and specific examples like ALT and AST. Learn more about how amino acids are synthesized and transformed in the body.
