Identification of Bioactive Peptides by High Resolution Liquid Chromatography-ElectroSpray Mass Spectrometry

摘要

A bioactive peptide database of electospray mass spectra (ESI-MS) was establishedduring the development of high resolution liquid chromatographic ESI-MS analytical methods with a magnetic sector instrument. High resolution ESI-MS data for a variety of bioactive peptides, including substance P (and related peptides), bradykinins, bombesins (and related peptides) and a Conus snail toxin, were acquired over a wide mass range by scanning the magnetic sector and calibrating externally with polyethylene glycol standards. Multiply charged ions were observed and errors between observed and theoretical monoisotopic molecular weights were typically in the 5 to 30 ppm range for the bioactive peptides with magnetic sector resolutions between 2500 and 4000 (10% valley definition). Isotopic clusters for charge states of up to +5 were fully resolved, facilitating the rapid and unambiguous assignment of charge states and calculation of monoisotopic molecular weights. Under CAD/MS conditions both bn and yn-series sequence ions were generally observed, enabling either full or partial amino acid sequencing of bioactive peptides, their degradation products and fragments generated by tryptic digestion.