trimethylate

Trimethylate is a term used in chemistry to denote the action of adding three methyl groups to a substrate, yielding a triply methylated product. In practice, trimethylation is the more common term, but trimethylate appears in some contexts as a verb form or in compound names. The resulting species may be a substituted amine, an ether, or another heteroatom bearing three methyl substituents, depending on the starting material and reaction conditions.

In organic synthesis, trimethylation can be achieved with methylating agents such as methyl iodide, dimethyl sulfate, or methyl triflate, often in the presence of a base. Reactions may proceed in steps or by using a single, potent methylating reagent. In biochemistry, three methyl groups can be transferred to substrates by methyltransferases using S-adenosylmethionine as the methyl donor. Histone proteins frequently display trimethylation on lysine residues (for example H3K4me3, H3K9me3, H3K27me3), a modification linked to regulation of gene expression and chromatin structure.

Because trimethylate is less commonly used as a noun than trimethylation, many texts treat trimethylate as a verb or as part of a compound name rather than as a standalone class of substances. Caution is warranted when handling reagents used for methylation due to toxicity and environmental concerns.

See also: Methylation; Trimethylamine; Histone methylation; S-adenosylmethionine; Methylating agents.