Tandem Mass Spectrometry For Determining The Amino Acid Sequence Of Cyclic Peptides And For Assessing Interactions Of Peptides And Metal Ions

There is little need to “sing the praises” of tandem mass spectrometry (MS/MS) to mass spec-trometrists. It is necessary, however, to ensure that the message is conveyed to structural chemists. The acceptance of MS/MS as an important tool for structure determination can be gauged easily by the growing number of literature studies in which the technique is used and by the commitment of instrument manufacturers to the design and marketing of tandem mass spectrometers. This growth is precipitated certainly by the advent of fast atom bombardment (FAB) in 1981.¹The use of this “soft” ionization technique opened up a wealth of opportunities for mass spectrometry in the analysis of biomolecules. Probably the largest contributor to the popularity of the combined technique of FAB and MS/MS is the relative ease with which MS/MS can be merged with FAB once a suitable instrument is incorporated into a laboratory. Recent reviews on the application of MS/MS to biomolecules,²including peptides³and lipids,⁴,⁵attest to the acceptance and utility of FAB and MS/MS.