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One-Carbon Metabolism

Integrated network of folate- and methionine-dependent reactions that transfer one-carbon units for nucleotide synthesis, amino acid metabolism, and methylation reactions.

Also: 1C metabolism, Folate-methionine cycle

One-carbon metabolism links folate (carrier of 1C units), B12 (methionine synthase cofactor), B6 (serine hydroxymethyltransferase, cystathionine pathway), riboflavin (MTHFR cofactor as FAD), and choline/betaine (alternative methyl donor). The cycle generates S-adenosylmethionine (SAM), the universal methyl donor for DNA, histone, neurotransmitter, and phospholipid methylation. Disruption underlies hyperhomocysteinemia, megaloblastic anemia, and neural tube defects.

How one textbook covers it

  • Modern Nutrition in Health and Disease, 12th ed. — Ch 26: Folate

    One-carbon metabolism links folate (carrier of 1C units), B12 (methionine synthase cofactor), B6 (serine hydroxymethyltransferase, cystathionine pathway), riboflavin (MTHFR cofactor as FAD), and choline/betaine (alternative methyl donor). The cycle generates S-adenosylmethionine (SAM), the universal methyl donor for DNA, histone, neurotransmitter, and phospholipid methylation. Disruption underlies hyperhomocysteinemia, megaloblastic anemia, and neural tube defects.

Related terms

Choline, Folate, Homocysteine, MTHFR, SAM, Vitamin B12