Overview of Protein Biochem

Question 1

Conditionally essential amino acids

Answer 1

can be made by the body, but in limited capacity. in states of high consumption (critical illness), deficiency may develop

Question 2

Glucogenic amino acids

Answer 2

can be used as substrates for glucoeneogenesis

Question 3

Ketogenic amino acids

Answer 3

when they are broken down, they generate acetyl CoA. produce ATP via TCA cycle or be used for ketone synthesis

Question 4

Two intracellular pathways for protein degradation

Answer 4

ubiquitination (targets protein for degradation by proteosome) and lysosomes

Question 5

What must happen before an amino acid can be used as a precursor for gluconeogenesis?

Answer 5

NH2 must be removed (transamination, usually in the liver)

Question 6

Prototypical transamination reaction

Answer 6

amino acid donates (transaminase) NH2 to alpha-ketoglutarate –> L-glutamate + alpha keto acid

regeneration of alpha-ketoglutarate –> NH3 release –> leaves body via urea cycle

Question 7

first key regulated step in protein catabolism

Answer 7

NH3 + (carbamoyl phosphate synthase 1) –> carbamoyl phosphate

Question 8

Second key regulated step in protein catabolism

Answer 8

glutamate + (glutamate dehydrogenase) –> alpha ketoglutarate

Question 9

Importance of glutamine in protein catabolism

Answer 9

important N acceptor in periphery –> liver and kidney –> donates N to glutamate