Methylation


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methylation

[‚meth·ə′lā·shən]
(organic chemistry)
A chemical process for introducing a methyl group (CH3‒) into an organic compound.

Methylation

 

the replacement of a hydrogen, metal, or halogen atom by a methyl group,—CHs; it is effected by the action of various methylating agents—for example, methyl iodide, CH3I; dimethyl sulfate, (CH3O)2SO2; methylsulfuric acid, CH3OSO3H; methyl esters of organic sulfo acids; methanol, CHjOH; and dimethyl ether, (CH3)2O. Methylation is widely used in organic synthesis in industry. For example, methylation with dimethyl sulfate is used in the synthesis of pharmaceuticals (for example, metapyrin); amidopyrine is prepared by methylation with formaldehyde and a reducing agent, usually formic acid.

Aromatic hydrocarbons are readily methylated by the action of methyl chloride or dimethyl ether in the presence of AlCl3. Methylaniline and dimethylaniline are prepared industrially by methylation of aniline with methanol over A12O3 at high temperatures:

Methylation with diazomethane is widely used to produce methyl esters of carboxylic acids under laboratory conditions, according to the formula

R—COOH + CH2N2→RCOOCH3 + N2

B. L. DIATKIN

References in periodicals archive ?
However, the hunt for DNA methylation based biomarkers has been limited in the past to one gene at a time approaches," said Nathan Lakey, CEO and president of Orion Genomics.
Methylation refers to naturally occurring chemical modifications of DNA that regulate gene function.
One of these is called DNA methylation, he explained.
The assay combines SureSelect, the leading target-enrichment platform, with bisulfite sequencing, the gold standard for DNA methylation research and the first comprehensive discovery system.
4) Previous epidemiological studies probing DNA methylation and arsenic exposure have isolated methylation patterns within specific genes of interest, (5,6) and a few have begun to assess epigenome-wide changes.
DNA methylation is a biochemical process involving the modification of DNA that plays an important role in development and disease.
professor in the Department of Obstetrics & Gynecology and the Institute of Environmental Health Sciences, director of epigenomics, and program leader in the Center for Urban Responses to Environmental Stressors, he and his research team revealed that lead exposure can cause specific changes in DNA methylation, which can be detected in dried blood spots beyond one generation.
Because DNA methylation is a biological mechanism whereby cells control gene expression in a complex manner (stochastic dynamics, phase variation, and bistability) (Riggs and Xiong 2004), we hypothesized that mean regression analyses may not capture associations that occur primarily in the tails of the outcome distribution.
DNA methylation is different from histone methylation, with the effects of the latter being more transient.
DNA methylation is an important epigenetic marker of the transcriptionally repressed state of the genes (Jones and Takai, 2001).
119 MICRORNA-29 REGULATES DNA METHYLATION BY TARGETING ONCOGENE TET2
DNA methylation involves the addition of a methyl group to cytosine, occurring primarily in the context of CpG dinucleotides.