Protein Processing

Question 1

Ammonia disposal

Answer 1

transamination: amino group transferred fromAA to ketoglutrate –> glutamate (safe transport for ammonia)- requires pyridoxal phosphaet
Deamination- glutamate –> ammonia release } mainly in liver
Urea synthesis: via urea cycle- in mitochondria . Ammonia + bicarb –> carbomyl phosphate (control step), then 2nd AA group added to form arginine and release urea

Question 2

Gluconeogenesis

Answer 2

Pyruvate to oxaloacetate (can’t leave mitochondria) –> malate or aspartate –> cytosol –> back to OAA –> Phosphoenolpyruvate/PEP (PEP carboxykinase)
fructose 1,6 bisphosphate –> fructose 6 phosphate (fructose 1,6, bisphosphatase)–> glucose 6 phosphate –> glucose (glucose 6 phosphatase)

Question 3

Gluconeogenesis controlled by

Answer 3

glucose and low energy levels

low glucose and/or high energy –> gluconeogenesis

Question 4

Glucose-alanine cycle

Answer 4

sustains transamination in peripheral tissue- without it will run out of alpha-ketoglutamate

Question 5

Alcohol and gluconeogenesis

Answer 5

inhibits it and lowers blood glucose
ethanol metabolism –> large amounts NADH, pyruvate and alanine–> lactate–> prevents glycerol –> glyceraldehyde 3 phosphate; inhibits gluconeogenesis