We have developed four new activity-based probes:

HA-Ahx-Ahx-Ub-VAE (VAE= vinyl azido ester, human sequence, synthetic); UbiQ code: UbiQ-216
HA-Ahx-Ahx-Ub-VAA (VAA= vinyl azido amide, human sequence, synthetic); UbiQ code: UbiQ-217
HA-Ahx-Ahx-Ub-VPE (VPE= vinyl pentynyl ester, human sequence, synthetic); UbiQ code: UbiQ-218
HA-Ahx-Ahx-Ub-VPA (VPA= vinyl pentynyl amide, human sequence, synthetic); UbiQ code: UbiQ-219

These are all activity-based probes for deubiquitinating enzymes (DUBs). The probes are labelled on the N-terminus with the HA peptide sequence (YPYDVPDYA) derived from the influenza hemagglutinin protein and allows for the sensitive identification or purification of DUBs by anti-HA antibodies and/or anti-HA-agarose. The HA tag is separated from the N-terminus by two 6-aminohexanoic acid (Ahx) linkers for efficient recognition of the tag. The alkyne group (in UbiQ-218 and 219) or the azide group (in UbiQ-216 and 217) in the warhead allows for further modification by click chemistry.