Flashcard: Folate and B12 Metabolism Essentials — 16 carte

Folate — role?

DNA synthesis, methylation, RBC formation

B12 — role?

DNA synthesis, methylation, neurological function

Folate sources?

Leafy vegetables, beans, fruits, yeast, mushrooms, animal meat

B12 sources?

Animal products: liver, milk, fish, eggs; microbial synthesis

Folate structure?

Pteroylmonoglutamate with pteridine, p-aminobenzoic acid, glutamate residues

B12 structure?

Corrin ring with central cobalt ion

Folate absorption site?

Jejunum after conversion to monoglutamate by conjugase

B12 absorption site?

Ileum, requires intrinsic factor for uptake

Folate absorption mechanism?

Converted to monoglutamate, transported via PCFT transporter

B12 absorption mechanism?

Bound to intrinsic factor, absorbed via receptor-mediated endocytosis in ileum

One-carbon metabolism — importance?

Transfers methyl groups, supports DNA synthesis and methylation

Key enzyme linking folate and B12?

Methionine synthase, uses methylcobalamin to convert homocysteine to methionine

Deficiency signs?

Megaloblastic anemia, neurological deficits, neural tube defects

Assessment markers?

Serum folate, serum B12, methylmalonic acid, homocysteine

Folate-B12 interaction?

Both needed for methylation; B12 deficiency causes folate trap, masking deficiency

Folate deficiency — effects?

Megalo-blastic anemia, neural tube defects, impaired DNA synthesis