Amino Acid Metabolism Flashcards Preview

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Flashcards in Amino Acid Metabolism Deck (11):
1

Nitrogen fixation

Process of reducing atmospheric N2 (non-reactive) to ammonia (nucleophilic)

2

Common entry points for nitrogen in organic molecules

Glutamate and glutamine
Alpha-ketoglutarate + NH4 -> glutamate (enzyme: glutamate dehydrogenase)

3

Transamination reaction

Transferring the alpha-amino group of glutamate to another molecule (typically an alpha-keto acid)

4

Where are the 20 common amino acids derived from?

Metabolic intermediates from glycolysis, the pentose phosphate pathway, and the TCA cycle

5

The urea cycle

Conversion of toxic ammonia to urea, which is less toxic and can be excreted
Process occurs mainly in the liver

6

Net reaction of urea cycle

NH3 + HCO3- + aspartate + 3 ATP -> urea + fumarate + 2 ADP + 2 Pi + AMP + PPi

7

Preliminary step of urea cycle

Synthesis of carbamoyl phosphate from bicarbonate and Pi from ATP

8

Step 1 of urea cycle

Ornithine + carbamoyl phosphate -> citrulline
Enzyme: ornithine transcarbamoylase

9

Step 2 of urea cycle

Citrulline + aspartate -> argininosuccinate
Enzyme: argininosuccinate synthetase

10

Step 3 of urea cycle

Argininosuccinate -> arginine
Enzyme: argininosuccinate lyase
Fumarate is released

11

Step 4 of urea cycle

Arginine -> urea + ornithine
Enzyme: arginase