SIMULTANEOUS SEQUENCE ANALYSIS OF AMINO- AND CARBOXY- TERMINI

摘要

The present invention relates to a new method for identifying polypeptides bydeducing the amino acid sequence of the carboxy and amino termini by a massspectrometer analysis. The method comprises the steps of dissociating highlycharged peptide precursor ions (e.g., z 4) using electron transferdissociation inducing anions followed by removal of those reagents andintroduction of a second, proton transfer inducing anion type. The second PTRreaction duration is adjusted to convert the ETD products to primarily the + 1charge-state to reduce the highly charged c and z-type fragments, producing anm/z spectrum containing a series of c and z-type fragment ions that are easilyinterpreted to reveal the sequence of the amino and carboxy terminus,respectively.