Mass spectrometric analysis of head-to-tail connected cyclic peptides.

Tandem mass spectrometry is an extremely useful tool for high sensitive sequence identification of peptides. In the case of cyclic peptides fragmentation can easily be performed for sequence analysis. However, analysis is usually tedious due to the lack of a defined beginning and end of the sequence. Since cyclic peptides are a highly interesting class of compounds especially for the pharmaceutical industry, ways have to be found to identify their strictures. In this work we demonstrate how software and dedicated analytical strategies can be used for detailed analysis of these substances.