MCP - Schmitt - One C Metabolism - 2/24 Flashcards
(24 cards)
What is the amino acid precursor of GABA?
Glutamate
What is the amino acid precursor of Histamine?
Histidine
What is the amino acid precursor of Melanin?
Tyrosine
What is the amino acid precursor of Melatonin?
Tryptophan
What is the amino acid precursor of Serotonin?
Tryptophan
What is the amino acid precursor of Niacin?
Tryptophan
What is the amino acid precursor of Thyroxine?
Tyrosine
What is the cofactor involved in the production of DOPA from tyrosine?
BH4, tatrahydrobiopterin
What enzyme catalyzes catechols, and is inhibited by some anti-depressants?
monoamine oxidase
What is the defect in albinism?
Albinos cannot convert tyrosine to melanins
What is the amino acid precursor of NAD+?
Tryptophan
Glutamate decarboxylase is dependent on what cofactor to turn glutamate into GABA?
Pyridoxal phosphate
In what kind of reaction is pyridoxal phosphate needed?
Any decarboxylation reaction occurring next to an amino group
Bioton is a carrier of this, most oxidized one-carbon group.
CO2
T/F: THF carries all manner of 1-carbon groups, including CO2.
False. THF does not carry CO2
What effect do the drugs methotrexate and aminopterin share?
Lower folate levels in the body by inhibiting dihydrofolate reductase
What is the main role of SAM, s-adenosylmethionine?
It is a major carrier of methyl groups.
It can donate methyl groups to a variety of molecules.
Elevated levels of homocysteine have been strongly correlated with was disease?
atherosclerosis
By giving B12 , folate and pyridoxal phosphate, you promote the degradation of homocysteine.
T/F: Vitamin B12 is a methyl group carrier.
True
B12 = cobalamin
What is homocysteinuria?
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)
Deficiency of THF and B12 leads to what disease?
Pernicious anemia, aka megablastic anemia (immature rbc released into circulation)
Long term B12 deficiency results in what symptoms?
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.
What is the most abundant form of THF in the blood?
5-methyl-THF
Why is folate supplementation potentially dangerous?
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.
