LAUSR

Mass spectrometry is a powerful tool for de novo sequencing of novel proteins. Recent efforts in this area have mainly focused on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Here we present an alternative method, capillary electrophoresis tandem mass spectrometry (CE-MS/MS), for sequencing novel monoclonal antibodies. Using less than 200 ng in total of tryptic digest sample in a triplicated measurement, CE-MS/MS with pH mediated focusing successfully sequenced mAb infliximab with 100 % sequence coverage and 100 % accuracy for the light chain and 96 % coverage and 93 % accuracy for the heavy chain. It was also demonstrated that CE-MS/MS gives comparable results, and in some cases, even better results, than LC-MS/MS when used as a stand-alone technique. A combined workflow using both CE-MS/MS and LC-MS/MS was also used to sequence a novel antibody, anti-CD-176, resulting in the first proposed sequence for this mAb.