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PSI-MOD Protein Modifications Ontology

This repository contains the Human Proteome Organization (HUPO) Proteomics Standards Initiative (PSI) Protein Modifications Ontology (PSI-MOD). It is the source repository of the PSI-MOD obo file, main deliverable PSI-MOD.

The PSI working group PSI-MOD

The description of the joint activities of the PSI-MOD working group can be found here.

If you would like to comment on the PSI-MOD document, please submit a new issue through GitHub.

PSI-MOD file formats : OBO, OBO-XML and OWL

The master source file for this ontology is the obo file and the OWL file is a derivative of it.

The previously available OBO-XML file format has been deprecated in favor of the more highly supported OWL file format. Pull Requests MUST include updated OBO and OWL files. The ROBOT Tool is used to create compliant OWL files from the OBO using this syntax:

robot.bat convert --input "path-to-obo-file\psi-mod.obo" --output "path-to-obo-file\psi-mod.owl"


The present repository is replacing the previous location at SourceForge CVS site ( This link (*checkout*/psidev/psi/mod/data/psi-mod.obo) found in various files can be safely substituted with the PSI-MOD PURL: (