Deamination and Ornithine Cycle

Question 1

What is Deamination?

Answer 1

• A removal of a amine group to form ammonia

Question 2

What is the Ornithine Cycle?

Answer 2

• Toxic ammonia from deamination is converted to urea in a sequence of enzyme controlled reactions

Question 3

Why do we convert ammonia into urea for excretion?

Answer 3

• urea is less soluble and water is needed

Question 4

How does the Ornithine Cycle Work?

Answer 4

• Excess amino acid cannot be stored
• Amino acids are deaminated in mitochondria of liver cells
• Deamination: Removal of amine group from amino acid
• The amine group is converted to ammonia
• ammonia enters the ornithine cycle.
• converted to urea
• Citrulline moves from Mitochondria into the cytoplasm of the liver cell
• urea is remved by Kidneys
• High concentration if urea in blood
• Decreases the water potential of blood
• Increases water reabsorption by kidneys