Purity ~50% (SDS-PAGE). Source: Recombinant corresponding to aa150-end of human Nedd 4 with N-terminal FLAG tag, expressed in a Baculovirus infected Sf9 cell expression system (NM_006154). Specific Activity: 0.0027pmol/min/ug Assay conditions: 50ul reaction mix (4mM ATP, 5mM MgCl2, 1mM DTT, E1 (0.5ug UBE1), E2 (2.8ug UBCH5a), Biotin-Ubiquitin (0.5ug) and Nedd4 (0-2ug ) in 50mM Tris pH 7.4) incubate for 30 min at 37°C, then add to streptavidin coated plates and incubate for 30 min at 37°C. Add antibody against Nedd4, incubate 1 hour. Finally, incubate 1 hour with the Europeum-labeled secondary antibody. Time resolved fluorescence measured at RT. (lambda-exc=330nm, lambda-em=620nm). Applications: Suitable for use in conjunction with E1 and E2 for the study of enzyme kinetics, screening inhibitors and selectivity profiling.