The Ups and Downs of Repeated Cleavage and Internal Fragment Production in Top-Down Proteomics.

ABSTRACT: Analysis of whole proteins by mass spectrometry, or top-down proteomics, has several advantages over methods relying on proteolysis. For example, proteoforms can be unambiguously identified and examined. However, from a gas-phase ion-chemistry perspective, proteins are enormous molecules that present novel challenges relative to peptide analysis. Herein, the statistics of cleaving the peptide backbone multiple times are examined to evaluate the inherent propensity for generating internal versus terminal ions. The raw statistics reveal an inherent bias favoring production of terminal ions, which holds true regardless of protein size. Importantly, even if the full suite of internal ions is generated by statistical dissociation, terminal ions are predicted to account for at least 50% of the t

SUBMITTER: Lyon YA 

PROVIDER: S-EPMC5786485 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature