Phosphorylase B isCA∆-SIDC. We also included PhosB, a homodimer whose CIx data are presented in Figure and S4, and SID data in Figure . In terms of CIx, the plot only shows a slight decrease in the drift time as a function of cone voltage, otherwise there are no distinct features that suggest quaternary structure rearrangement. This drift time decrease does suggest mass loss, which is confirmed when the deconvolved and centroided mass spectra collected with cone settings of 10 V and 160 V are compared for the 21+ charge state. The spectrum collected at a cone = 100 V features a deconvolved mass that is ~156 Da lower than that collected at cone = 10 V. At the highest cone voltage, 160 V, the deconvolved mass is ~300 Da lower than that collected at cone = 10 V. While structural rearrangement is not evident, the higher cone voltage clearly helped with in-source protein cleanup, i.e., loss of adducts such as (H2O), (NH4+) and (CH3COO-).