Demethylase

Demethylases are enzymes that remove methyl (CH3-) groups from proteins and other substances. They are utilized in a variety of processes, such as in chemotaxis signal transduction.

A good example of a demethylase is the activated (i.e. phosphorylated) form of the CheB protein, which demethylates MCPs (methyl-accepting chemotaxis proteins). MCPs sense extracellular attractants and repellents in bacteria like E. coli in chemotaxis regulation. Because CheB removes methyl groups from a glutamate and creates, as a result of this demethylation, a methanol and a glutamic acid residue, CheB is more specifically termed a methylesterase.