Lecture 26: Amino Acid Metabolism And The Urea Cycle

Question 1

First off, see slide 5-7.

Answer 1

Yeah. Great start.

Question 2

What dictates the lifetime of a protein?

Answer 2

• Nterminus AA dictate protein lifetime
• Defective E3 causes protein accumulation
• Common diseases regarding protein aggregation?
• See Slide 8

Question 3

What does she describe as the Exectutioner?

Answer 3

Proteasome: Large Protease Complex

• See Slide 9, especially red box.

Question 4

See Slides 10-11

What are the three steps of the big picture?

Answer 4

1. Aminotransferase
2. Glutamate Dehydrogenase
3. Urea Cycle

Question 5

Describe the transamination step of amino acid metabolism

Answer 5

• Shuffling amino groups
  1. α-Amino group is transferred to an α ketoacid
  2. Coupled reactions
  3. Enzymes called Step #1: aminotransferases

Question 6

What are three features of amino acid metabolism

Answer 6

• Reversible!
• Directionality dictated by concentrations Keto acid Amino acid Keto acid
• Driven forward by removal of NH 4 +

Question 7

Describe aminotransferase

Answer 7

• Require coenzyme:
• Pyridoxal 5-phosphate (PLP)
• Derivative of Vitamin B6
  Clinical relevance: –
  – Alanine transaminase (ALT)
• Aspartate transaminase (AST )

Question 8

• Incomplete:

How is nitrogen removed out of muscle?

Answer 8

Resume at slide 15. And should check previous slides to make sure they make sense.
* Can’t let NH4 out as…shit. It’s one of these types of slide sets.

Removed as 4