For 14, the native hBChE in the control sample featured a mass of 60069 ± 1 Da (ProtParam 61 calculated mass from the primary sequence: 60069.2 Da), while the 20-min 14-incubated sample produced a species with mass of 60183 ± 1 Da (Figure ). This mass difference of 114 ± 1 Da, is in good accordance with the expected mass difference for the morpholinocarbamoylated hBChE (114.1 Da). Interestingly, injection of the same 14-treated sample incubated for more than 60 min, showed only the presence of the free, noncarbamoylated hBChE, after deconvolution.