9. Amino acids as fuel

Question 1

Protein degradation

Answer 1

Occurs in the 26S PROTEASOME

Question 2

Answer 2

Amino Acid

Question 3

Answer 3

Alpha ketoacid

Question 4

Answer 4

Urea

Question 5

removal of Nitrogen

Answer 5

Question 6

Transamination

Answer 6

Question 7

Oxidative deamination

Answer 7

Question 8

ALT (Alanine aminotransferase )

Answer 8

Alanine to pyruvate

Question 9

AST (Aspartate aminotransferase)

Answer 9

Glutamate to Asparate

Question 10

Urea Cycle

Answer 10

Question 11

Fate of Urea

Answer 11

Urea diffuses from the liver

is transported in the blood to the kidneys

filtered and excreted in the urine

A portion of the urea diffuses from the blood into the intestine

cleaved to CO2 and NH3 by bacterial urease

ammonia is partly lost in the faeces and is partly reabsorbed into the blood

Question 12

A blockage in the Urea pathway leads to:

Answer 12

an increase in NH4+ in blood (hyperammonenmia)

After birth infants are lethargic and vomit periodically

Coma, brain damage and death may follow

Treatment includes ↓ total protein intake

Question 13

Failure of urea cycle

Answer 13

Hyperammonaemia

Encephalopathy

• Feeding disorders
• Mental problems
• Death/severe disabilities

Question 14

Management of hyperammonaemia

Answer 14

Low protein diet

Amino acid replacements (α-ketoacids)

Question 15

Alaptonuria

Answer 15

Disruption in the degradation of Phe and Tyr

Can’t break the benzene ring

Question 16

Maple Syrup Urine Disorder

Answer 16

Can’t degrade Val, IIe, Leu

Rise of α-ketoacids in blood and Urine (sweet smell)

Question 17

Phenylketonuria

Answer 17

Disruption in the degradation of Phe

Can lead to mental retardation

Question 18

Melanin production

Answer 18

Synthesized from Tyrosine

Lack of Tyrosinase= albinism

Tyrosine > L-DOPA > Dopaquinone