Polymorphic distribution of proteins in solution by mass spectrometry: The analysis of insulin analogues.

The characterization of conformational and oligomeric distribution of proteins is of paramount importance for the understanding of the correlation between structure and function. Among the bioanalytical approaches currently available, the electrospray ionization-mass spectrometry (ESI-MS) coupled to ion mobility spectrometry (IMS) is the best suited for high resolution identification with high sensitivity, allowing the in situ separation of oligomeric and conformational species. We tested the performance of the ESI-MS technique along with the IMS separation approach on a broad variety of insulin and insulin analogues with distinct oligomeric distribution pattern.

Assignment of polymorphic species of insulin analogues in ion mobility mass spectroscopy.

Electrospray ionization - ion mobility spectrometry - mass spectrometry (ESI-IMS-MS) allows the identification of protein polymorphic distribution of protein conformers and oligomers. We report the detailed identification of the species observed with commercially available pharmaceutical preparation of wild-type, regular human insulin.