Chapter 27. Recent Developments in the Mass Spectrometry of Peptides and Proteins.

Abstract

Publisher Summary This chapter discusses some of the recent developments of mass spectrometry in the analysis of peptides and proteins. An absolute requirement for the successful mass spectrometric analysis of any compound is the production of ions of the molecule in the gas phase. In this method, the compound of interest is ionized and desorbed from a surface by the application of a strong electric field. Several different types of mass analyzers are used to determine the mass-to-charge ratio (m/z) of ions produced from peptides and proteins. These include the double focusing electric and magnetic deflection mass analyzer (MA), the quadrupole MA, the time-of-flight MA, and the Fourier transform ion cyclotron resonance MA. The most important single piece of information obtained with mass spectrometry that helps to characterize a peptide or protein is its molecular weight. Mass spectrometric peptide mapping has become an established and powerful structural tool for the analysis of proteins. The general strategy involves chemical or enzymatic degradation of the protein, followed by mass spectrometric molecular weights (MW) determination of the resulting peptides. One of the most important applications of mass spectrometry for protein analysis is the detection and definition of posttranslational modifications. Frequently, posttranslational modifications are initially detected by MW determination of chemically or enzymatically generated peptide fragments of the protein. Mass spectrometry has also been used to provide information on the carboxytermini of proteins, the structure of the peptide network of pneumococcal peptidoglycans, iodination sites in cytochrome C, and the correct MW of proteins. During the production of peptide ions large amounts of energy are deposited in the ionized molecule. At the end of the chapter, it is predicted that mass spectrometry is likely to become an increasingly important analytical tool for the biomedical scientist who works with peptides and proteins.