Mfm - Folates And B12

Front 1

Relationship between B12 and Folate

Back 1

B12 deficiency leads to folate deficiency

B12 deficiency leads to increased folate derivatives

Front 2

Megaloblastic anemia (re: B12 and folate)

Back 2

Caused by either B12 or folate deficiency

Reversed by large doses of folate (if caused by B12 deficiency)

Front 3

Neurological symptoms (re: B12 and folate)

Back 3

B12 causes them, but not seen in patients with folate deficiency

Front 4

Megaloblastic anemia (signs)

Back 4

Low red blood cells

Large blood cell precursors (starting building up for division, but couldn't divide)

Lots of RNA in precursor cells

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Pernicious anemia

Back 5

Caused by B12 deficiency

Megaloblastic anemia with neurological signs (starts with sensory and then progresses to motor control)

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Folates (use in cells)

Back 6

Used to transfer methyl groups

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THF

Back 7

Central intermediate in folate cycle

Folate derivative (tetrahydrofolate)

N5 or N10 are the places that a methyl group is added

Front 8

B12 and folate (interaction)

Back 8

B12 is used to convert N5-methyl-THF to THF

Front 9

Dihydrofolate reductase

Back 9

Reduces DHF to THF to allow it to enter the folate cycle again

DHF is produced in dUMP to dTMP

Front 10

dUMP to dTMP

Back 10

Necessary for DNA synthesis

THF to DHF accomplishes the conversion

Front 11

Sulfa drugs (re: folate)

Back 11

Antibiotics that stop synthesis of folate in bacteria

Don't affect humans, because we eat, rather than make, folate

Increase oxidative stress

Front 12

Anti-tumor drugs

Back 12

Starve tumors of folates (can't reproduce)

Methotrexate and aminopterin

Front 13

Leucovorin rescue

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Give N5-THF

Solves problem of not working DHF reductase (from methotrexate)

Front 14

Methotrexate

Back 14

Binds to DHF reductase

Starves cells of folates

Normal cells aren't as affected, because they aren't dividing as much

Front 15

SAM (synthesis)

Back 15

From ATP and methionine

Front 16

SAM and Folate

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After SAM transfers a methyl group somewhere, it needs to resynthesize methionine

N5-THF gives the methyl group to do that

Converts N5-THF into THF; uses a B12 derivative to do so

Front 17

B12 (structure)

Back 17

Have a cobalt and similar to hemoglobin (without Fe)

Also called cobalin

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Cbl-IF

Back 18

Intrinsic factor is needed to absorb the vitamin in the ileum

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N2O and B12

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Nitrous oxide can oxidizes Cobalt to an unusable state

Can lead to B12 deficiency

Front 20

B12 reactions

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Conversion of homocysteine to methionine (the one that uses N5-THF)

Conversion of malonyl-CoA to succinyl-CoA

Front 21

Neurologic problems from B12

Back 21

No conversion of malonyl-coa to succinyl-coa

Leads to weird myelin