Lecture 7\

Question 1

What are some ways amino groups are removed?

Answer 1

Aminotransferase, glutamate dehydrogenase, lyase (dehydratase), glycine cleavage enzyme

Question 2

What must happen to carbon backbones to enter glycolysis and TCA cycle?

Answer 2

modified - remove carbons, open aromatic ring, remove thiol groups, etc.

Question 3

Give examples of how amino acid degradations connect to other metabolic pathways.

Answer 3

Asp/Arg degradation/synthesis — Urea cycle. Ser-Gly — THF cycle. Met degradation — SAM cycle.

Question 4

Free ammonia in the cell can be taken up by

Answer 4

Glutamine syntheses and glycine synthetase (

Question 5

Why can’t ketoegnic amino acids be used to synthesis glucose via glucogenesis (2)?

Answer 5

1. Pyruvate dehydrogenase is irreversible so pyruvate cannot be made from acetyl CoA.
2. Entry of acetyl CoA into TCA cycle is carbon neutral (2 carbons that enter to the TCA cycle is consumed as CO2)