decomposed carboxymethylated methionine From DeltaMass: Average Mass: -48 Average Mass Change:-48 References:Anal. Biochem. Vol 216 No.1 p141 M MOD:00950 OBSOLETE because this modification has not been seen/reported on since this original publication in 1994 and carboxymethylation of proteins is common enough for this mass shift to have been seen in the intervening 25+ years. modification from DeltaMass PSI-MOD true