Riboflavin (B2) Flashcards Preview

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Flashcards in Riboflavin (B2) Deck (12)
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1

Kinases

An enzyme (flavokinase) phosphorylates riboflavin to form FMN.
Requires ATP.

Enhanced by magnesium.

2

Absorption

Free riboflavin by energy dependent sodium independent carrier RFT2.

Bile facilitates absorption.

FMN dephosphorylated to riboflavin to enter portal blood to go to liver.

3

Riboflavin carrier proteins (RCP)

Expressed in cells with high metabolic activity.

Pregnancy induces synthesis of RCP's.

Mediate supply of riboflavin to fetus.

4

RDA

1.3 mg men
1.1 mg women

5

Assessment

Static: urine

6

Redox

Dehydrogenation and hydroxylation reactions.

7

B2 in energy production rxns

Oxidative decarboxylation of pyruvate.

Electron transport: succinate dehydrogenase composed of FAD and 3 S atoms.

Fatty acid beta oxidation

8

B2 in other vitamin metabolism

B6, B12, and folate metabolism.

Niacin from tryptophan (NE).

Reduces glutathione which recycles vitamin C

9

Deficiency

Ariboflavinosis: Cheilosis (mouth sores), inflamed tongue, neuropathy, weakness.

Rarely deficient in isolation. Usually alongside other deficiency due to being used in metabolism of folic acid, B6, vit K, B12, vit C recycle.

10

Megadosing/ UL

No UL.

Migraine therapy and cataract prevention.

11

Excretion

Urine

12

Sources

Animal products: milk, eggs, meat.
Legumes. Green vegetables.

Found as FMN of FAD.