I no longer work on protein kinases but when I did, PhosphoGRID is the kind of database that I would have wanted to see. It features:
- Useful information returned from a simple search form
- Data for download in plain text format with no restrictions or requirements for registration
All it lacks is a RESTful API, but nothing is perfect :-)
Published in the little-known but often-useful journal Database:
PhosphoGRID: a database of experimentally verified in vivo protein phosphorylation sites from the budding yeast Saccharomyces cerevisiae.