? Group of answer choices alanine arginine asparagine glycine glutamate glutamine phenylalanine proline tryptophan tyrosine
The Correct Answer and Explanation is:
The amino acids that are synthesized using 2-oxoglutarate (also known as alpha-ketoglutarate) as a starting point are glutamate, glutamine, proline, and arginine.
Here’s an explanation:
1. Glutamate:
- 2-oxoglutarate is directly involved in the synthesis of glutamate. Through reductive amination, 2-oxoglutarate accepts an amino group from glutamate dehydrogenase (GDH) to form glutamate. This reaction is important for maintaining amino acid balance in cells and is a key process in nitrogen metabolism.
2. Glutamine:
- Glutamine is synthesized from glutamate through an enzyme called glutamine synthetase, which adds an additional amino group to glutamate, forming glutamine. Thus, glutamine is indirectly derived from 2-oxoglutarate.
3. Proline:
- Proline is synthesized from glutamate in a two-step process. First, glutamate is reduced to glutamate-5-semialdehyde, and then it undergoes a cyclization reaction to form proline. So, proline is another amino acid that is ultimately derived from 2-oxoglutarate.
4. Arginine:
- The synthesis of arginine also involves glutamate. The process begins with glutamate being converted into ornithine via a series of enzymatic reactions, and then ornithine is converted into arginine. Therefore, arginine is another amino acid whose synthesis is dependent on 2-oxoglutarate.
Other Amino Acids:
- Amino acids such as alanine, asparagine, glycine, phenylalanine, tyrosine, and tryptophan do not directly derive from 2-oxoglutarate. These amino acids are synthesized from other precursors or pathways. For example, alanine is derived from pyruvate, while phenylalanine and tyrosine are derived from phenylalanine and tyrosine biosynthetic pathways.
Thus, glutamate, glutamine, proline, and arginine are the amino acids synthesized using 2-oxoglutarate as a precursor.
