Amino acid modifications for mass spectrometry
Managing amino acid modifications for mass spectrometry in R.
Unimod is a public domain database, distributed under a
copyleft licence: “a
copyright notice that permits unrestricted redistribution and
modification, provided that all copies and derivatives retain the same
permissions.”The aim is to create a community supported, comprehensive database of
protein modifications for mass spectrometry applications. That is,
accurate and verifiable values, derived from elemental compositions,
for the mass differences introduced by all types of natural and
artificial modifications. Other important information includes any
mass change, (neutral loss), that occurs during MS/MS analysis, and
site specificity, (which residues are susceptible to modification and
any constraints on the position of the modification within the protein
or peptide).