Trimethylglycine / BetaineTMG · 甜菜碱 Betaine

Place · Level 3 · Supplement

甘氨酸戴 3 个甲基 · 同型半胱氨酸再甲基化双轨制副路 · MTHFR 突变者最受益 · 一碳代谢最后一块拼图

Glycine with 3 methyls

Stop 1/5

身份 · 三甲基化的甘氨酸

TMG (trimethylglycine) = glycine + three methyl groups (-N(CH₃)₃⁺); its formal chemical name is betaine — named because it was first isolated from sugar beet (*Beta vulgaris*) in 1866.

Chemical structure:

The amine group (-NH₂) of glycine is replaced by three methyls → a quaternary ammonium compoundPositive and negative charges coexist (-N(CH₃)₃⁺ + -COO⁻) → a zwitterion, which is the root of its 'osmolyte' (osmoprotectant) propertyWater-soluble, mildly sweet (this is also where the '-ine' suffix in 'betaine' comes from)
Two independent roles:

1. Cellular osmoprotectant: protects cellular protein structure under hypertonic (high-salt) or dehydrated conditions (a member of the same osmolyte family as taurine / sorbitol / creatine)
2. Methyl donor: via the BHMT enzyme, it donates a methyl group to homocysteine → methionine (next scene)

Two ways the body obtains TMG:

Food: wheat germ / whole wheat / spinach / beetroot / quinoa / seafood (scallops, shrimp)Endogenous synthesis: choline → betaine — choline dehydrogenase + BADH in mitochondria oxidize choline in two steps into TMG
The second path links TMG directly to the choline story — choline is not just raw material for phospholipids / ACh / hepatic lipid transport, it is also the endogenous precursor of TMG and therefore supports the dual-track methylation system.

Read story

本站提供科普与一般性建议，不替代医师诊断或处方；有症状或正在服药请咨询合格医师。 Educational content, not medical advice — consult a clinician for diagnosis or treatment.

Back