Diubiquitin substrates with true ubiquitin isopeptide bonds

Internally Quenched Fluorescence (IQF) substrates allows the measurement of De-Ubiquitylase (DUB) activity. These IQF-DiUbs substrates are unique as they mimic true Ubiquitin isopeptide bonds present in polyubiquitylated proteins.

These substrates are wild type Ubiquitin, in which the C terminal extremity is conjugated via an isopeptide bond to the specific lysine (K11, K48 or K63) of a second Ubiquitin molecule. This bound forms thus a diubiquitin quenched fluorescent FRET (IQF DiUb) pair; each ubiquitin being labeled with a single molecule of either a fluorescent reporter (i.e. TAMRA) or a highly efficient quenching dye. A cleavage of the IQF DiUb by Deubiquitylases leads to separation of the fluorophore with the quencher leading to an increase of the fluorescence (see figure).



Available IQF substrates:

DiUb K-48

DiUb K-63

DiUb K-11         Panels
DiUb K48-1 DiUb K63-1 DiUb K11-4 DiUb K48 1-6 panel
DiUb K48-2 DiUb K63-2 DiUb K11-6 DiUb K63 1-6 panel
DiUb K48-3 DiUb K63-3 DiUb K11-8 DiUb K-48 1-6 & DiUb K-63 1-6 panel
DiUb K48-4 DiUb K63-4    
DiUb K48-5 DiUb K63-5    
DiUb K48-6 DiUb K63-6    

Application notes: