1) Gene expression 
Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms. == In biochemistry == In biochemical systems, the process of demethylation is catalyzed by demet...
The enzymatic removal of methyl groups. ... (05 Mar 2000) ... 
Type: Term Pronunciation: dē-meth′i-lā′shŭn Definitions: 1. The enzymatic removal of methyl groups.