AA Metabolism 2

Question 1

Name two important aminotransferases (AT) name pairs also?
Are AT rxn’s reversible?
What pair of reactant and products are always involved in AT rxns?
This AT is in ______ cell, but mostly in ______

Answer 1

ALT (alainine(A) - pyruvate) , 
AST (aspartate(A) - oxaloacetate)
Only non essential AA - AT can reverse rxn.
A-Ketogluterate, glutamate
every, liver and kidney

Question 2

High Serum AST, ALT are indicators of _____

Answer 2

Liver damage; necrosis

Question 3

During exercise mm. releases _____ (3),

Using a coupled AT pathway explain how the mm accomplished its task of reducing free NH3, and making alanine

Answer 3

Leucine, isoleucine, valine, using their respective AT’ases, they make and Alpha keto acid, and glutamate. Glutame is retured to Alpha keto gluterate by ALT, and an amino group is added to pyruvate making alanine.

Question 4

What cofactor do all AT need?
After eating AA can be degraded by removing a ____ from AA; When AA supply is low, it can be sythesized by _____ NH3 to a ____

Answer 4

B6

NH3, adding NH3 to a A- keto- acid

Question 5

Name the important enzyme in Oxidative Deamination?
Where is this enzyme found in cells?
Describe the bidirectional reaction

Answer 5

Glutamate Dehydrogenase
Mitochondria
Glutamate + NAD+ –> A-Ketogluterate + NADH + NH3
A-Ketogluterate + NADPH + NH3 –> Glutamate

Question 6

Oxidative deamination is pushed toward A-Ketogluterate + NADPH + NH3 when ____?
A-Ketogluterate is a _______ intermediate; NH3 is sent to ______

Answer 6

ADP, GDP, No Glucose, NO meal

krebs cycle (generates Energy)
Urea Cycle

Question 7

What are the three ways to get glutamate?
Name the enzyme involved in glutamine/glutamate formation

note 50% of our AA is in glutamine form - (NE AA); Donates amines for NT formation

Answer 7

1) amination of A-Ketogluterate
2) De-amination of glutamine (2NH3)

glutamine –Glutaminase –> glutamate
glutamate –Glutamine synthase –> glutamine

Carboxylation of GABA (NT) at alpha carbon

ATP need to add an amine group but not remove!

Question 8

Explain how (4) NE amino acids are synthesized from glycolysis intermediate: 3- phosphoglycerate?

Answer 8

3PGlycerate –>Serine —> [pyruvate, glycine, cysteine]

pyruvate —> alanine

Question 9

What are the two ways to get Aspartate?

Answer 9

1) amination of oxaloacetate (TCA)

2) De-amination of asparagine (2NH3)

Question 10

What happens to the a-keto acids that are a product of transamination?

Answer 10

The carbon backbone of the keto acid are converted to intermediates of energy generating pathways –> forming pyruvate Acetyl CoA, TCA intermediates, acetoacetate

Question 11

Excess intake of protein leads to ______, usually from bone. This leads to and increased risk for ____, and _____

Answer 11

increased urine calcium

kidney stones, osteoperosis

Question 12

If Carb intake is low, AA can be used to make _______, which through TA can become _____; What two hormones stimulate gluconeogenesis from AA, and are insulin antagonists?

Answer 12

pyruvate, oxaloacetate —> gluconeogenesis

Cortisone/Cortisol