Author Archives: Michael V. Murray

Figure 2: Intact ESI-MS spectra of both nonsuccinylated and succinylated proteins; upper figures represent the full charge envelope of the two proteins, and lower figures illustrate a narrower m/z charge range. Each m/z charge state of the nonsuccinylated protein was observed to be a primary species, whereas significant heterogeneity was seen for the charge states of the succinylated protein.

Mass Spectrometric Conjugate Characterization: Process Qualification of Recombinant Protein–Hapten Conjugation

Conjugated protein biotherapeutics such as PEGylated proteins (with polyethylene glycol), antibody–drug conjugates (ADCs), and protein–haptens often present unique analytical challenges related to characterizing the conjugation aspect of their manufacturing processes. Analytical characterization of this class of proteins requires knowledge of the sites of conjugation, the degree of conjugation, and the drug-to-protein ratio. Here we present case studies in development of reliable methods based on mass spectrometry (MS) to characterize a protein–hapten drug substance during late-phase process validation. This protein is…