Applications of mass spectrometry for the structural characterization of recombinant protein pharmaceuticals.

Therapeutic proteins produced using recombinant DNA technologies are generally complex, heterogeneous, and subject to a variety of enzymatic or chemical modifications during expression, purification, and long-term storage. The use of mass spectrometry (MS) for the evaluation of recombinant protein sequence and structure provides detailed information regarding amino acid modifications and sequence alterations that have the potential to affect the safety and activity of therapeutic protein products. General MS approaches for the characterization of recombinant therapeutic protein products will be reviewed with particular attention given to the standard MS tools available in most biotechnology laboratories.

Development of LC-IMS-CID-TOFMS techniques: analysis of a 256 component tetrapeptide combinatorial library.

Recent improvements in ion mobility/time-of-flight mass spectrometry techniques have made it possible to incorporate nano-flow liquid chromatography and collision induced dissociation techniques. This combination of approaches provides a new strategy for detailed characterization of complex systems--such as, combinatorial libraries. Our work uses this technology to provide a detailed analysis of a tetrapeptide library having the general form Xxx1-Xxx2-Xxx3-Xxx4 where Xxx1 = Glu, Phe, Val, Asn; Xxx2 = Glu, Phe, Val, Tyr; Xxx3 = Glu, Phe, Val, Thr; and Xxx4 = Glu, Phe, Val, Leu--a system that is expected to contain 256 different peptide sequences.

Development of high-throughput liquid chromatography injected ion mobility quadrupole time-of-flight techniques for analysis of complex peptide mixtures.

The development of a multidimensional approach involving high-performance liquid chromatography (LC), ion mobility spectrometry (IMS) and tandem mass spectrometry is described for the analysis of complex peptide mixtures. In this approach, peptides are separated based on differences in their LC retention times and mobilities (as ions drift through He) prior to being introduced into a quadrupole/octopole/time-of-flight mass spectrometer. The initial LC separation and IMS dispersion of ions is used to label ions for subsequent fragmentation studies that are carried out for mixtures of ions.