Amino Acid Metabolism

Question 1

In what types of cells will you find aminotransferases?

Answer 1

Liver, kidney, muscle

Question 2

Other than the TCA cycle, what pathways are primary consumers of TCA intermediates?

Answer 2

Gluconeogenesis

Fatty acid synthesis

Question 3

What complex is sensitive to ROS, creates succinyl CoA and NADH/FADH2?

Answer 3

Alpha-ketoglutarate dehydrogenase

Question 4

What are the names of vitamins B1, 2, 3, and 5 and what cofactors do they help provide?

Answer 4

B1: Thymine, TPP
B2: Riboflavin, FAD+
B3: Niosin, NAD+
B5: Pantothenic acid, CoA

Question 5

The branched-chain alpha-keto acid dehydrogenase (BCKD) is in the same family as what other dehydrogenase and uses which 5 cofactors?

Answer 5

Family = PDC
Cofactors = TPP, Lipoic acid, CoA, NAD+, FAD

Question 6

Is homocystein good or bad?

Answer 6

Bad

Question 7

What does homocystein accumulation in the kidney cause?

Answer 7

Homocystine formation (disulfide bonding)

Question 8

What is the pathway of Met to Succinyl CoA?

Answer 8

Met –> SAM –> SAH –> Homocysteine –(B6, 12, folic acid)–> Succinyl CoA

Question 9

What causes the defective metabolism of homocystein?

Answer 9

Vitamin deficiencies in B6, B12, folic acid

Question 10

What is hyperhomocysteinemia associated with?

Answer 10

Atherosclerotic heart, stroke, eye lens dislocation

Question 11

What leads to Phenylketonuria and what is a treatment for it?

Answer 11

Defects in THB production.
Sapropterin treatment (synthetic THB)

Question 12

What amino acid is not converted to melanin in albinism?

Answer 12

Tyrosine

Question 13

MAO and COMT breakdown which neurotransmitters?

Answer 13

Dopamine: HVA

Norepinephrine/Epinephrine: VMA

Question 14

What is a pheochromocytoma?

Answer 14

Adrenal gland tumor

Question 15

What does an MAO inhibitor do?

Answer 15

Acts as anti-depressant by inhibiting degradation of neurotransmitters in synaptic cleft

Question 16

How can hyperthyroidism be treated?

Answer 16

Agents to block iodination of thyroglobulin and decrease T4/T3 production

Question 17

T/F: Glutathione acts as a neurotransmitter.

Answer 17

False, antioxidant

Question 18

What affect does increased levels of acetaminophen have on glutathione levels?

Answer 18

Depletes them because they bind together

Question 19

Elevated gamma-glutamyl transpeptidase (GGT) is a marker for what?

Answer 19

Hepatobiliary dysfunction

Question 20

What do nitrodilators do to BP?

Answer 20

Decrease BP and relax smooth muscle

Question 21

Explain nNOS.

Answer 21

NOSI, on neuronal cells

Messenger and modulator of neurotransmitter release

Question 22

Explain iNOS.

Answer 22

NOSII, Phagocytic inducible isoform,

Fights infections in macrophages

Question 23

Explain eNOS.

Answer 23

NOSIII, on Endothelial cells,

Prevents vascular smooth muscle contraction and platelet aggregation by increasing Ca2+ and intracellular cGMP

Question 24

Serum cardioselective creatine kinase is a marker for what and peaks when?

Answer 24

M.I.

Peaks 10-24 hrs post M.I.

Question 25

Carbamoyl phosphate synthetase II is the enzyme that catalyzes the first step of de novo synthesis of what?

Answer 25

Pyrimidines

Question 26

What stimulates and inhibits carbamoyl phosphate synthetase II?

Answer 26

Stimulates: PRPP Inhibits: UTP

Question 27

What autosomal recessive defect leads to accumulation of orotic acid and orotic aciduria?

Answer 27

UMP synthase

Question 28

Is urea increased/decrease for high protein/carb diets?

Answer 28

Protein - Increased urea | Carb - Decreased urea

Question 29

Which amino acids are strictly ketogenic?

Answer 29

Leu, Lys

Question 30

Which amino acids are both ketogenic and glucogenic?

Answer 30

Ile, Trp, Phe, Tyr, Thr

Question 31

What test is used for nitrogen balance and what is the normal range?

Answer 31

Blood Urea Nitrogen (BUN) | 3.0-8.2 mg/dL

Question 32

Which aminotransferase is found only in the cytoplasm and which is found in both the cytoplasm and mitochondria?

Answer 32

Cytoplasm: ALT Both: AST

Question 33

Which is a more specific diagnosis of liver disease, ALT or AST?

Answer 33

ALT