Mechanism and multiplicity of methyltransferases

Reactions of methylation imply the transfer of a methyl group from the cofactor S-adenosyl-L-methionine (22, Figure 10; SAM) to the substrate It is important to note that the methyl group in SAM is bound to a sulfonium center, giving it a marked electrophilic character and explaining its reactivity. Furthermore, it becomes pharmacokinetically relevant to distinguish methylated metabolites in which the positive charge has been retained or lost.

A number of methyltransferases are able to methylate small molecules.41-43 Thus, reactions of methylation fulfil only three of the four criteria defined above, since the methyl group is small compared to the substrate.

Was this article helpful?

0 0

Post a comment