Probing asymmetric charge partitioning of protein oligomers during tandem mass spectrometry

- We present the asymmetric charge partitioning factor (ACPF).
- We apply ACPF to monomer ejection of cytochrome c dimer and beta amylase tetramer.
- ETD indicates similar cytochrome c ESI-monomer and ejected monomer structures.
- ETD fragment ions from the dimer undergo asymmetric charge partitioning.
- ETD fragment ions from dimer can have 2-fold higher ACPF than ejected monomer.