Synthesis of Glucose Fromaminoacids

Synthesis of Glucose from Amino Acids (Gluconeogenesis)

  • Definition: Conversion of glucogenic amino acids into glucose via gluconeogenesis.

  • Process:

    1. Glucogenic amino acids (e.g., alanine, glutamine) are deaminated to form pyruvate or TCA cycle intermediates (e.g., oxaloacetate).

    2. These intermediates enter the gluconeogenic pathway in the liver (and kidney).

    3. Final product is glucose, released into blood to maintain blood sugar.

  • Example with real pathway:
    Alanine → Pyruvate → Oxaloacetate → Phosphoenolpyruvate → Glucose
    This is called the glucose-alanine cycle.

  • Key enzymes:

    • Alanine transaminase (ALT)

    • Pyruvate carboxylase

    • PEP carboxykinase

    • Fructose-1,6-bisphosphatase

    • Glucose-6-phosphatase

Short Answer:

Glucogenic amino acids (e.g., alanine, glutamine) are deaminated to form pyruvate or TCA intermediates, which via gluconeogenesis in liver/kidney form glucose. Example: Alanine → Pyruvate → OAA → PEP → Glucose.

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