[doof]

does S-Adenosyl methionine only methylate amine groups or does it methylate a number of different groups, if so what is the best way to specifically methylate an amine?

[tmartin]

Which other groups are present that you do not want to methylate (a free alcohol I'm guessing)?  Also, why SAM?  It seems to be a pretty exotic reagent to use to methylate an amine...is this in a peptide or on a protein?

[doof]

I'm a biologist i like exotic things 

there is no OH but there is an aromatic ring

yes it is in a peptide

[tmartin]

Hehe, ok fair enough  .

If there is no free hydroxyl group, I would think you could effect facile methylation of the amine without worrying about the aromatic ring, that really shouldn't get involved.  Without knowing the exact system it is kind of hard to predict, but I would guess you could use something as simple as methyl iodide (assuming no other reactive species like thiols, acids, ketones maybe even).  If it is a primary amine you may have to be careful with your equivalents to avoid over methylation.

Of course, since you like exotic things, and s-adenosyl methionine is used to transfer methyl groups, I don't see why you couldn't use that either. 

[nj_bartel]

You can't use methyl iodide to take a primary amine to a secondary amine with any kind of good yield, regardless of equivalents, can you?

[doof]

thanks guys