Four types of information have been taken into account to calculate delta m/z in PRIDE Inspector:
- Peptide Sequence - Required
- Post translational modifications - Optional
- Precursor m/z - Required
- Precursor charge - Required
The calculation can be broken down into the following steps:
1. Calculate peptide mass: simply sum the masses of all the amino acids in the peptide.
2. Calculate PTM mass: simply sum the masses of all the post translational modifications in the peptide.
3. Calculate theoretical mass: [Peptide mass - PTM mass - 18 dalton].
4. Calculate precursor mass: [(Precursor m/z * Precursor charge) - (Precursor charge * 1 dalton)].
5. Calculate detla m/z: [(Precursor mass - Theoretical mass)/Precursor charge].