Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Comparison of the theoretical spectrum (top) of an unmodified protein sequence EPPLSQETFS and the theoretical spectrum (bottom) of a modified proteoform EPPLS[phosphorylation]QETFS, in which the serine residue is phosphorylated. Only N-terminal fragment peaks are included in the theoretical spectra to simply the comparison. The fragment peaks in the box are shifted to the right by 79.97 Da in the bottom spectrum because of the phosphorylation
