Does anyone know of a good cysteine alkylation reagent that doesnt
result in a modification of 58 daltons? i am looking for a
carboxymethylation on a cysteine (using esi ms/ms), and want to
alkylate the rest of the cysteines with a reagent with an MW that is
significantly different. by the way, I tried NEM and didnt get a
great reaction apparently, so are there any other reagents people use
with mass spec? or what conditions do people use for NEM alkylation?