The research will focus on the search for a group of enzymes reversing one of the evolutionally oldest protein modifications, known as urmylation. The latest studies have shown that this process is one of the most important mechanisms protecting cells from oxidative stress. Whereas the molecular basis of the modification has been known, no enzyme reversing the process has been identified so far. In Dr Kwaśna’s project, specific active probes reacting with the targeted group of enzymes will be developed. The captured proteins will be identified by means of mass spectrometry, and further research will concentrate on understanding the mechanism of their functioning and the role they play in cells.