The massXpert project aims at providing (bio)chemists with a software
package allowing the following:

* User-specific atom definitions and polymer chemistry definitions;
* Powerful sequence editing with user-defined glyphs for each monomer
and monomer chemical modification. Multi-region selections;
* Polymer sequence chemical/enzymatic cleavage;
* Intramolecular cross-linking, like disulfide bonds with total resolution
of the peptides generated upon enzymatic cleavage;
* Gas-phase fragmentation of oligomers;
* Mass-to-charge ratio calculations with inline change of ionization agent;
* Calculation of net electrical charge and of isoelectric point (even by
taking into account monomer modifications if polymer is a protein);
* Simulation of isotopic patterns for any chemical formula and z charge;
* A number of plugins allow 1) translation of the sequence from one format
to another (using a dictionary, like between the 1-letter code and the 3-letter
code of proteins) 2) conversion of number format according to any localized
number format 3) sort mass lists.

WWW: https://salsa.debian.org/debichem-team/massxpert