Current Methods for the Characterization of Posttranslational Modifications in Therapeutic Proteins Using Orbitrap Mass Spectrometry

This chapter describes the current development of Orbitrap mass spectrometry (MS) methods for the characterization of protein modifications to support the discovery and development of protein therapeutics in the pharmaceutical industry. Orbitrap instrumentation is that three different fragmentation techniques, collision-induced dissociation (CID), higher-energy collision dissociation (HCD), and electron transfer dissociation (ETD), are available in the same instrument. The chapter focuses on routine peptide sequencing and posttranslational modifications (PTM) analysis using HCD approach. It presents a novel approach designed to identify PTMs that are labile to collision dissociation. The chapter provides the application of HCD on peptide sequencing and PTM analysis using NISTmAb as a model. It also describes the application of ETD on characterization of labile PTMs using glycopeptides as examples. The chapter presents the current and emerging Orbitrap methods that are universal and can be applied to the analysis of other protein therapeutics.