This manual page documents briefly the tandem-mass package that brings a mass spectrometric software
software for peptide sequencing and protein identification.
This software has a very simple, unsophisticated application programming interface (API): it simply takes
an XML file of instructions on its command line, and outputs the results into an XML file, which has been
specified in the input XML file. The output file format is described at
`http://www.thegpm.org/docs/X_series_output_form.pdf'.
Unlike some earlier generation search engines, all of the X! Series search engines calculate statistical
confidence (expectation values) for all of the individual spectrum-to-sequence assignments. They also
reassemble all of the peptide assignments in a data set onto the known protein sequences and assign the
statistical confidence that this assembly and alignment is non-random. The formula for which can be found
here. Therefore, separate assembly and statistical analysis software, e.g. PeptideProphet and
ProteinProphet, do not need to be used.