Assay Method Information

Assay Name:  Biochemical Assay
Description:  USP28: Each assay was performed in a final volume of 20 μL in assay buffer containing 20 mM Tris-HCl (pH 8.0, (1M Tris-HCl, pH 8.0 solution; Corning 46-031-CM)), 2 mM CaCl2) (1M Calcium Chloride solution; Sigma #21114) 2 mM BME (2-Mercaptoethanol; Sigma 63689-25ML-F), 0.01% Prionex (0.22 μM filtered, Sigma # G-0411), and 0.01% Triton X-100. Stock compound solutions were stored at −20° C. as 10 mM in DMSO. Up to 1 month prior to the assay, 2 mM test compounds were pre-dispensed into assay plates (Black, low volume; Corning #3820) and frozen at −20° C. Prestamped assay plates were allowed to come to room temperature on the day of the assay. For the screen, 100 nL of 2 mM was pre-dispensed for a final screening concentration of 10 μM (DMSO(fc)=0.5%). Enzyme (USP28, construct USP28 (USP28-5(1-1077)-TEV-6*His; LifeSensors) concentration and incubation times were optimized for the maximal signal-to-background while maintaining initial velocity conditions at a fixed substrate concentration. The final concentration of the enzyme in the assay was 400 pM. Final substrate (Ub-Rh110; Ubiquitin-Rhodamine 110, R&D Systems # U-555) concentration was 25 nM with [Ub-Rh110]<<Km. 10 μL of 2× enzyme was added to assay plates (pre-stamped with compound) either simultaneously with 2×Ub-Rh110 or preincubated with USP28 40 minutes prior to the addition of 10 μL of 2×Ub-Rh110 to compound plates. Plates were incubated stacked for 90 minutes at room temperature before fluorescence was read on the Envision (Excitation at 485 nm and Emission at 535 nm; Perkin Elmer) or on the PheraSTAR (Excitation at 485 nm and Emission at 535 nm; BMG Labtech).
Affinity data for this assay
 

If you find an error in this entry please send us an E-mail