Fate of the Carbon Skeleton of Amino Acids

🪶Amino acids can be classified based on the fate of their carbon skeletons during metabolism.

🪶They are grouped into two main categories:

Glucogenic and Ketogenic amino acids.

Some amino acids belong to both categories.

1.Glucogenic Amino Acids:

🪶These amino acids are broken down into intermediates that can be used in the citric acid cycle (TCA cycle).

🪶The intermediates include pyruvate, alpha-ketoglutarate, succinyl-CoA, fumarate, and oxaloacetate.

🪶These intermediates can be converted into glucose through gluconeogenesis, making glucogenic amino acids important for maintaining blood sugar levels and producing glycogen.

2.Ketogenic Amino Acids:

🪶These amino acids are degraded into acetyl-CoA or acetoacetate.

🪶Acetyl-CoA can be converted into ketone bodies (such as acetoacetate and β-hydroxybutyrate), which can be used as an energy source by various tissues, especially during fasting or low carbohydrate intake.

🪶Since acetyl-CoA cannot be converted into glucose, ketogenic amino acids do not contribute to gluconeogenesis.

3.Both Glucogenic and Ketogenic Amino Acids:

🪶Some amino acids can yield products that serve as precursors for both glucose and ketone bodies.

🪶These amino acids contribute to both energy production and glucose synthesis.

Amino Acid Classification:

💫Glucogenic Amino Acids: Alanine, Arginine, Asparagine, Aspartate, Cysteine, Glutamine, Glutamate, Glycine, Histidine, Methionine, Proline, Serine, Threonine, and Valine.

💫Ketogenic Amino Acids: Leucine and Lysine.

💫Both Glucogenic and Ketogenic Amino Acids: Isoleucine, Phenylalanine, Threonine, Tryptophan, and Tyrosine.

This classification highlights the metabolic versatility of amino acids and their importance in both energy production and biosynthetic pathways.

Pyruvate:--

Alanine, Cysteine, Glycine, Hydroxyproline, Serine, Threonine

Acetoacetate:--

Leucone, Lysine

Glutamate :--

Arginine, Histidine, proline

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