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Nutrigenomique et épigénétique

Methionine Methylation

Key metabolic conversion of methionine to SAM to feed cellular methylation reactions.

Definition

Metabolic pathway in which methionine is converted into S-adenosylmethionine (SAM), the universal methyl group donor for DNA, protein, and lipid methylation reactions.

How it works

Methionine, an essential sulfur-containing amino acid obtained through diet or synthesized from homocysteine, is the precursor to S-adenosylmethionine (SAM). SAM is the most important methyl donor in the body, providing methyl groups to methylate DNA, histones, neurotransmitters, and phospholipids. This reaction is catalyzed by the methionine adenosyltransferase enzyme. After donating the methyl group, SAM becomes S-adenosylhomocysteine, which is converted into homocysteine, closing the cycle. Adequate methionine and its cofactors (B12, folate) intake are critical to maintain DNA methylation and epigenetic regulation.

Role

Precursor amino acid of S-adenosylmethionine, the primary methyl donor for epigenetic and metabolic regulation.

Examples

  • Red meat
  • Eggs
  • Fish
  • Pumpkin seeds
  • Cheese
  • Brazil nuts

Recommendations

Ensure adequate intake of protein-rich methionine (approximately 1.2-1.6g per kg body weight for adult adults). Combine methionine intake with adequate supplementation of B12 and folate to optimize the methylation cycle. Individuals with genetic polymorphisms affecting the methylation cycle may require a personalized nutritional approach.

Key takeaway

Methionine is the fundamental precursor to SAM, which feeds all essential methylation reactions.

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