Characterization of IgG and IgM Monoclonal Antibodies by Superconducting Tunnel Junction Cryodetection MALDI TOF Mass Spectrometry

摘要

Murine IgG1 κ, MOPC-21 was examined by MALDI TOF STJ MS. The use of an ion's impact energy on the STJ cryodetector assisted in the assignment of a previous observed, but unidentified MALDI induced IgG fragment. Through various MS experiments and with the assistance of protein structure prediction software, we hypothesize that the fragment is coming from the κ-chain. Why this fragment forms is not clear. Murine IgM λ, MOPC-104E was examined intact at m/z ～ 1 MTh using MALDI TOF STJ MS. The singly and multiply charged IgM ions were observed to be broad, which may suggest variability within the complex via modifications, adduct retention, and/or fragmentation. IgM was reduced and alkylated and the reaction products were examined by MALDI TOF STJ MS where preliminary peak assignments have been made and unidentified peaks may explain the dispersity of the intact complex.