Bessesen Overview of Protein Biochemistry Flashcards Preview

DEMS Unit 2 Part 2 > Bessesen Overview of Protein Biochemistry > Flashcards

Flashcards in Bessesen Overview of Protein Biochemistry Deck (10):
1

AA subparts

- Amino Group
- Carboxyl group
- R group

2

How to usefully categorize AA

1. Chemically - acidic vs basic
2. Where do you get them from? - essential vs nonessential vs. conditionally (yes we could do this ourselves, but capacity is limited, esp during illness)
3. Special qualities - sulfur containing, branched chain, or aromatic
4. Nutritional - glucogenic (glucose) vs. ketogenic (acetyl-CoA)

3

Proteolysis

Start with whole protein and need to break down into AA

Occurs in 2 places:
1. GI tract - lots of different types of proteases
2. In a cell - break down receptors that you don't need anymore (2 pathways - ubiquitination and lysosomal destruction)

4

How to get alpha-AA to alpha-keto acid

Transamination - Exchange reaction

AA + alpha-ketoglutarate --> alpha-keto acid + glutamate

Note: you regen the keto acid with a different carbon skeleton

Not energy requiring or producing, entirely concentration driven

5

What are two aminotransferase reactions that we tend to monitor frequently?

ALT and AST

ALT:
Alanine --> pyruvate

AST:
Aspartate --> oxaloacetate

6

Glutamate --> alpha-ketoglutarate

1. Catalyzed by glutamate dehydrogenase
2. Nitrogen is leaving
3. Energy is being donated (NAD+ --> NADH)

To go in the other direction you require energy in the form of NADPH

7

Once the nitrogen comes off of glutamate, where does it go?

It goes into the Urea Cycle

8

Who is the peripheral carrier for nitrogen from peripheral tissues to the liver?

Glutamine & Alanine:
Glutamate + NH3 --> Glutamine

Glutamine has the extra nitrogen (2 nitrogens), and can go to the liver

Alanine - delivers carbon but also delivers nitrogen via transamination reaction

9

What takes nitrogen off of glutamine in the liver?

Glutaminase

10

CO2 + 2ATP + Ammonia leads to what?

Carbamoyl Phosphate - energy requiring

RLS:
Catalyzed by Carbamoyl phosphate synthetase I