1,10 phenanthroline

1,10-phenanthroline (o-phenanthroline) is a chelator with a high affinity for divalent metal ions.  While not specific for DUBs, it has been shown to be a potent inhibitor of JAMM-type isopeptidases through chelation of the active site Zn2+ ion.  As such, o-phenanthroline is widely used when preparing cell lysates for the enrichment of proteins bearing K63-linked polyubiquitin chains which are especially sensitive to DUBs in the JAMM family.