Extending SDRF for Top-down

- Top-down:
- MS2 fragmentation method: ETD most popular.
- Enzyme: Not applicable for TopDown, could be for middle-out.
- Needs to use specific enzymes.
- Label-free most of the time. But still, we see some SILAC experiments.
- precursor and mass tolerances are the same.
- Record the deconvolution algorithm + version. We may need to add also terms to PSI-MS including software, algorithms and versions.
- Fractionations are the same.
- PTM could be searched in two approaches: Dynamic PTMs provided by Uniprot XML and also targeted PTMs for example Oxidation M or phospho as in bottom-up.
- Maximum charge state for the deconvolution algorithm.
- Same issue with Variable and Fix modifications.
- [Resolution is relevant](https://www.ebi.ac.uk/ols4/ontologies/ms/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FMS_1000011)

Make differences in PSI-MS:
- Ontology for types of experiments of TopTown
- Topdown approaches
- Top-down
- Middle-down
- Targeted Top-down