C-13-ENRICHED METHYL ALKANESULFONATES - NEW LIPOPHILIC METHYLATING AGENTS FOR THE IDENTIFICATION OF NUCLEOPHILIC AMINO-ACIDS OF PROTEINS BY NMR

C-13 labelled methyl alkylsulfonates are low cost and easily accessible methylating agents. They were used as NMR probes, in association with DEPT C-13 {H-1} NMR and 2D reversed {H-1, C-13} correlation NMR for the identification of nucleophilic residues of proteins. This labelling technique allows to visualize the nature of the reactive amino acids and to distinguish between lysine and histidine nucleophilic residues.