Q. 18.70 - An Introduction to General, Organic, and Biological Chemistry

Question

What metabolic substrate(s) are produced from the carbon atoms of each of the following amino acids? 

a. leucine

b. asparagine

c. cysteine

d. arginine

Step-by-Step Solution

Answer

Metabolic substrate(s) produced from the carbon atoms of each of the following amino acids is (are):- 

a. leucine- Acetyl-CoA and acetoacetate. 

b. asparagine- Oxaloacetate. 

c. cysteine- Pyruvate 

d. arginine- $\alpha$-ketoglutarate 

Part(a) Step 1: Given information

We have been given a amino acid leucine.

We need to find out what metabolic substrate(s) are produced from the carbon atoms of given amino acid.

Part(a) Step 2: Explanation

 The seven products of amino acid carbon skeleton catabolism are:-

1. Oxaloacetate 
2.  $\alpha$-ketoglutarate
3.  Pyruvate 
4.  Fumarate
5. Succinyl coenzyme A (CoA) 
6. Acetyl CoA 
7. Acetoacetate 

 In the energy metabolism, they have a different fate.

Leucine is exclusively ketogenic and ultimately converted into acetyl-CoA and acetoacetate. 

Part(b) Step 1: Given information

We have been given a amino acid asparagine.

We need to find out what metabolic substrate(s) are produced from the carbon atoms of given amino acid.

Part(b) Step 2: Explanation

 The seven products of amino acid carbon skeleton catabolism are:-

1. Oxaloacetate 
2.  $\alpha$-ketoglutarate
3.  Pyruvate 
4.  Fumarate
5. Succinyl coenzyme A (CoA) 
6. Acetyl CoA 
7. Acetoacetate 

Asparaginase is an enzyme that converts asparagine to ammonia and aspartate. Transamination removes the amino group from aspartate, resulting in oxaloacetate.

Part(c) Step 1: Given information

We have been given a amino acid cysteine.

We need to find out what metabolic substrate(s) are produced from the carbon atoms of given amino acid.

Part(c) Step 2: Explanation

The seven products of amino acid carbon skeleton catabolism are:-

1. Oxaloacetate 
2.  $\alpha$-ketoglutarate
3.  Pyruvate 
4.  Fumarate
5. Succinyl coenzyme A (CoA) 
6. Acetyl CoA 
7. Acetoacetate 

Pyruvate is formed when cysteine is metabolized.

Part(d) Step 1: Given information

We have been given a amino acid arginine.

We need to find out what metabolic substrate(s) are produced from the carbon atoms of given amino acid.

Part(d) Step 2: Explanation

 The seven products of amino acid carbon skeleton catabolism are:-

1. Oxaloacetate 
2.  $\alpha$-ketoglutarate
3.  Pyruvate 
4.  Fumarate
5. Succinyl coenzyme A (CoA) 
6. Acetyl CoA 
7. Acetoacetate 

Arginase breaks down arginine to make ornithine. After that, ornithine is transformed to $\alpha$-ketoglutarate.