All diagrams in supply, synthesis and cofactors
One carbon metabolism and methyl donors
One-carbon transfer and SAM-dependent methylation are linked processes. A biochemical pathway is not a personalised supplement prescription.
One carbon metabolism and methyl donors
Scoped educational mechanism
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Read the diagram explanation and sources
Folate and cobalamin-dependent methionine synthase link one-carbon metabolism to methionine regeneration. SAM formed from methionine serves as a methyl donor in many reactions, including COMT and PNMT. After methyl donation, SAH is processed to homocysteine, which has several metabolic fates. This diagram omits intermediate steps and other folate functions. A common MTHFR variant alone does not demonstrate failed methylation, ADHD causation or benefit from a specific supplement.
- Folate-derived one-carbon → B12-dependent MTR: MTR
- B12-dependent MTR → Methionine and SAM: methionine
- Methionine and SAM → Methyl transfer: SAM
- Methyl transfer → SAH and homocysteine: SAH formation
- SAH and homocysteine → B12-dependent MTR: remethylation
What the diagram shows
Folate and cobalamin-dependent methionine synthase link one-carbon metabolism to methionine regeneration. SAM formed from methionine serves as a methyl donor in many reactions, including COMT and PNMT. After methyl donation, SAH is processed to homocysteine, which has several metabolic fates. This diagram omits intermediate steps and other folate functions. A common MTHFR variant alone does not demonstrate failed methylation, ADHD causation or benefit from a specific supplement.