‘Top down’ Analysis of Proteins for the Masses

During the last decade, ‘top-down analysis’ of proteins has been available to those scientists privileged by access to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Recent advances in ion trap and orbitrap technology coupled with developments like electron transfer dissociation (ETD) promise to make the ‘top-down’ strategy of protein analysis more widely available. Here, the general strategy of ‘top-down analysis’ is reviewed, an example of ‘top-down analysis’ of a small protein by ion trap mass spectrometry is described, and the importance of ETD is presented in the context of instrumentation based on the linear ion trap or as hybridized with transmission quadrupole mass spectrometers.