Amino Acids

Question 1

What is the definition of ketogenic?

Answer 1

Any amino acid that can be catabolized to A-CoA, or acetoacetate (a ketone body) is considered ketogenic

Question 2

What is the definition of glucogenic?

Answer 2

Any amino acid that can be catabolized to pyruvate or any intermediate of the TCA cycle is considered glucogenic

Question 3

What are the only non-glucogenic ketogenic amino acids?

Answer 3

Leucine and Lysine

Question 4

What are the sources of free ammonium?

Answer 4

1. Dietary sources; 2. Kidney; 3. Amines; 4. Purine and Pyrimidine catabolism

Question 5

How is free ammonium produced from the diet?

Answer 5

All free ammonium production occurs in the liver; 1. transdeamination of amino acids leads to free ammonium which then is converted to urea; 2. serine and threonine dehydratase generates NH4–> urea; 3. glutaminase produces NH4–>urea; 4. amino groups from other tissues (such as muscle) are transported to the liver in the form of alanine and glutamine; the NH4 is released by transdeamination and glutaminase, respectively

Question 6

How is free ammonium produced in the kidney?

Answer 6

Glutamine is converted to glutamate and free ammonium by renal glutaminase; glutamate in converted to a-KG and NH4 by renal glutamate dehydrogenase

Question 7

How is serine converted to free ammonium?

Answer 7

Serine dehydratase cleaves off NH4 from serine and creates Pyruvate as well

Question 8

How does threonine provide free NH4?

Answer 8

Threonine dehydratase cleaves NH4 off and creates alpha keyobutyrate as well

Question 9

How does glutamine provide NH4?

Answer 9

Glutaminase cleaves NH4 from glutamine to make glutamate