6. Nitrogen removal

Question 1

Hartnup

Answer 1

defective resorption of nonpolar AA (particularly trp)
(A, V, L, I, F, W)

can affect intestinal and renal absorption

Question 2

Cystinuria

Answer 2

defective resorption of dibasic AA

can affect intestinal and renal absorption

Question 3

what is the main nitrogen shuffler of the liver

Answer 3

glutamate

Question 4

what is the main nitrogen shuffler outside the liver

Answer 4

glutamine

Question 5

RLS of the urea cycle

Answer 5

carbamoyl phosphate synthetase 1

Question 6

what is the first step of nitrogen removal

Answer 6

oxidative deamination

Question 7

where does reabsorption of glucose and aas occur and how much is reabsorbed

Answer 7

PCT, 100%

Question 8

trp is a precursor for

Answer 8

serotonin, melatonin, niacin (precursor for NAD)

Question 9

deficiency of NAD affects what kind of tissue

Answer 9

tissue with high turnover rate or high energy demands

Question 10

PKU

Answer 10

defects in phenylalanine hydroxylase (PAH)
deficient in tyr, excess phe = toxic, can immitate alzheimer’s in the brain?

can sometimes treat with tyr supplements
Guthrie test for neonates

Question 11

Secondary PKU

Answer 11

defect in biosynthesis or regeneration of THB (tetrahydrobiopterin)

Question 12

Alkaptonuria

Answer 12

homogentisate oxidase defect

black urine

Question 13

Gout

Answer 13

high levels of uric acid or urate in the blood
diets rich in purines (beans, spinach, lentils, alcohol, meat and seafood) can trigger episodes

allopurinol used to treat. inhibits activity of xanthine oxidase

Question 14

what can result in more severe hyperammonemia?

Answer 14

defects in the mitochondrial transporters (ORNT1 and Citrin)

Question 15

what is the only enzyme in the urea cycle that is x-linked

Answer 15

ornithine transcarbamoylase

defects result in orotic aciduria

Question 16

what is the soluble form of bilirubin

Answer 16

conjugated (direct) bilirubin

Question 17

what enzyme is responsible for conjugating bilirubin?

Answer 17

UDP glucuronyl transferase (UGT)

Question 18

what is bilirubin conjugated to? (what is added to it)

Answer 18

glucuronate

Question 19

when might pathologic jaundice occur?

Answer 19

if there is an increased need to replace the number of red blood cells