MCP - Schmitt - One C Metabolism - 2/24

Question 1

What is the amino acid precursor of GABA?

Answer 1

Glutamate

Question 2

What is the amino acid precursor of Histamine?

Answer 2

Histidine

Question 3

What is the amino acid precursor of Melanin?

Answer 3

Tyrosine

Question 4

What is the amino acid precursor of Melatonin?

Answer 4

Tryptophan

Question 5

What is the amino acid precursor of Serotonin?

Answer 5

Tryptophan

Question 6

What is the amino acid precursor of Niacin?

Answer 6

Tryptophan

Question 7

What is the amino acid precursor of Thyroxine?

Answer 7

Tyrosine

Question 8

What is the cofactor involved in the production of DOPA from tyrosine?

Answer 8

BH4, tatrahydrobiopterin

Question 9

What enzyme catalyzes catechols, and is inhibited by some anti-depressants?

Answer 9

monoamine oxidase

Question 10

What is the defect in albinism?

Answer 10

Albinos cannot convert tyrosine to melanins

Question 11

What is the amino acid precursor of NAD+?

Answer 11

Tryptophan

Question 12

Glutamate decarboxylase is dependent on what cofactor to turn glutamate into GABA?

Answer 12

Pyridoxal phosphate

Question 13

In what kind of reaction is pyridoxal phosphate needed?

Answer 13

Any decarboxylation reaction occurring next to an amino group

Question 14

Bioton is a carrier of this, most oxidized one-carbon group.

Answer 14

CO2

Question 15

T/F: THF carries all manner of 1-carbon groups, including CO2.

Answer 15

False. THF does not carry CO2

Question 16

What effect do the drugs methotrexate and aminopterin share?

Answer 16

Lower folate levels in the body by inhibiting dihydrofolate reductase

Question 17

What is the main role of SAM, s-adenosylmethionine?

Answer 17

It is a major carrier of methyl groups.

It can donate methyl groups to a variety of molecules.

Question 18

Elevated levels of homocysteine have been strongly correlated with was disease?

Answer 18

atherosclerosis

By giving B12 , folate and pyridoxal phosphate, you promote the degradation of homocysteine.

Question 19

T/F: Vitamin B12 is a methyl group carrier.

Answer 19

True

B12 = cobalamin

Question 20

What is homocysteinuria?

Answer 20

Deficiency of cystathionine synthase, which catalyzes homocysteine + serine –> cystathionine
Children can have a stroke by age 4

Can also be caused by deficiency in the other pathway for homocysteine, to methionine, via homocysteine methyltransferase

Can also be caused by a THF deficiency (cofactor to B12)

Question 21

Deficiency of THF and B12 leads to what disease?

Answer 21

Pernicious anemia, aka megablastic anemia (immature rbc released into circulation)

Question 22

Long term B12 deficiency results in what symptoms?

Answer 22

Demyelination and degeneration of the spinal cord
This could also be related to intrinsic factor deficiency, which is needed to carry B12 from the gut to the blood stream.

Question 23

What is the most abundant form of THF in the blood?

Answer 23

5-methyl-THF

Question 24

Why is folate supplementation potentially dangerous?

Answer 24

The folate trap occurs when B12 is deficient, and folate gets trapped in the N5 methyl form, resulting in anemia. But if you give folate, such as in supplemental grains, then the B12 alone deficiency can produce irreversible neurological damage.