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Flashcards in 5 Folate Deck (33):
1

Folate aka

Folacin
Folic Acid (supplement / fortified name)

2

Folate named when

Folate in foods or body

3

folate chemical name

pteroylglutamate or pteroylglutamic acid

4

Folate structural features

Pteroic Acid + glutamate

5

C units attach where on folate for coenzyme form? ***

N-5 and N-10 ***

6

Folate activated by what reaction

reduction
- added hydrogens to 5,6,7,8 positions

7

Folate reductions

folate --> dihydrofolate (DHF) --> tetrahydrofolate (THF)

THF fully reduced form

8

What vitamins reduces (adds H) to folate?

Niacin NADH

9

tetrahydrofolate multiple forms formed by? what is the circulating form?

6 different forms made by addition of one carbon units
(must be in THF form to add carbon units)

N5-methyl THF = circulating form

10

Folate circulating form

N5-methyl THF

11

Majority of food folates are

polyglutamates

12

Necessary process to absorb folate

polyglutamates food form
- cleaved to monoglutamate to be absorbed

13

Drugs and folate

inhibit absorption
compete for transport

14

Folate uses what in order to travel

binding proteins
(many water soluble proteins use this)

15

Folate short term storage in cells by

adding back glutamates (polyglutamate)

16

Folate metabolic role

THF
acceptor of 1 carbon units
1. AA metabolism
2. nucleotide metabolism

17

Folate amino acid metabolism

1. Methionine synthesis (hcy --> met)
2. Histidine catabolism
3. interconversion of serine + glycine

18

Folate deficiency test

role of histidine metabolism
FIGLU

19

Folate Nucleotide metabolism

1. synthesis of purines and pyrimidines (adenine, guanine, uracil, thymine, cytosine)

2. DNA synthesis

20

Methotrexate

chemotherapy drug
slows conversion of DHF to THF

21

Folate food sources

Dark green vegetables
Corn, dried peas, beens, lentils
Fortified in white flour, corn meal, rich pastas

22

Folate deficiency symptoms

Macrocytic anemia (same as B12)
- decreased oxygen carrying capacity of blood
- weekness, depression

*increased homocysteine Hcy

Neural tube defects

23

Folate and b12

Same macrocytic anemia with deficiency
- Increasing folate will correct this but not the neurological effects of b12 deficiency

24

Diagnosing Folate deficiency

Histidine Load test (FIGLU test)
- Give excess histidine, measure FIGLU in urine after 24hrs
- High than folate deficiency

25

Folate vs Folic Acid (supplement form)

Folate LESS bioavailable

approximately 2:1 (on empty stomach)

26

Neural Tube Defects occur? prevented?

21-28 days post conception (before knowledge of pregnancy)
Folic acid supplementation

27

Folate Fortification Debate

important for women becoming pregnant, not so much others
can increase cancer risk

28

Folate and caner

Contribute to genetic stability (lowers colorectal cancer)
- proper function of Wnt cascade

Cancer cells need folate to maintain "tymidine synthesis" at a pace needed to maintain high rate of DNA synthesis
- paradoxical acceleration of carcinogenesis

Core issues (large area of study):
1. timing of exposure
2. level of exposure
3. folate versus folic acid

29

Current interest around folate stems around discovery of ?
Importance?

Single nucleotide polymorphism
- alternations in genes coding for folate dependent enzymes (5,10-methylene THF reductase "MTHFR")

Increase risk of disease (Neural tube defect and breast cancer)

30

Would B12 fortification help folate def?

Neural tube defects helped with B12
B12 fortification would not solve malabsorption problem

Large area of study. Still unknown

31

Homocysteine an intermediate of

Methionine metabolism

32

Diseases associated with homocysteine

CVD
- possible dementia/alzheimers

33

3 Homocysteine fates?
Needs?

Good:
remethylation to methionine (B12)
Transsulfeation to cysteine (B6)

Bad:
Release to blood

folate, b6 and b12