AA Degradation and Urea Cycle

Question 1

Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, arginine

Answer 1

essential AA

Question 2

essential AA for growth

Answer 2

Arginine

Question 3

Alanine, arginine, asparagine, cysteine, glutamate, glutamine, glycine, proline, serine, tyrosine

Answer 3

non-essential AA

Question 4

deficiency of tryptophan; 4 D’s plus neutral and aromatic AAs in urine and feces; treated with niacin

Answer 4

Hartnup’s disease

Question 5

4 D’s of Hartnup’s (like pellagra)

Answer 5

diarrhea
dermatitis
dementia
death

Question 6

defective transport system for basic AAs and cystine; cystine crystals cause UTIs and kidney stones; solublize cystine with penicillamine

Answer 6

cystinuria

Question 7

penicillamine

Answer 7

drug used to solublize cystine in cystinuria

Question 8

product of histidine breakdown; measures muscle breakdown

Answer 8

3-methyl histidine

Question 9

three ways body gets rid of ammonia

Answer 9

glutamate dehydrogenase, glutamine synthase, carbamoyl phosphate synthase I and II

Question 10

what does carbamoyl phosphate synthase do in the cytoplasm and mitochondria

Answer 10

• cytoplasm = pyrimidine nucleotide biosynthesis

- mitochondria = urea cycle

Question 11

major carrier of NH4+ groups in blood

Answer 11

glutamine

Question 12

transaminases, glutamate dehydrogenase, urea cycle

Answer 12

three ways AA-derive N is metabolized

Question 13

transaminase cofactor

Answer 13

pyridoxal phosphate (vit B6)

Question 14

why is Ala one of most abundant AA in blood

Answer 14

easily made from pyruvate, transported to liver, converted to glucose and gets rid of NH4+

Question 15

what enzyme catalyzes conversion of Ala to pyruvate

Answer 15

alanine aminotransferase (transaminase)

Question 16

where is glutamate dehydrogenase found, along with a-ketoglutarate and NADH

Answer 16

mito

Question 17

where does urea cycle occur

Answer 17

liver

Question 18

common sign of urea cycle enzyme deficiencies

Answer 18

ammonia intoxication

Question 19

defect in arginosuccinase, accumulate arginosuccinic acid

Answer 19

arginosuccinic aciduria

Question 20

defect in carbamoyl phosphate synthetase, high blood ammonia

Answer 20

hyper ammoniemia

Question 21

defect in arginase, high ammonia and arginine in blood; Arg, Lys, and Orn in urine

Answer 21

arginiemia

Question 22

defect in argininosuccinate synthetase; high blood NH4+ and citrulline; high urine citrulline; MENTAL RETARDATION

Answer 22

citrullinemia

Question 23

defect in ornithine transcarboxylase, high blood NH4+, oroate, and ornithine; high urine ornithine

Answer 23

hyper-ornithinemia