| Assay Method Information | |
| | In Vitro AKT1 Kinase Assay |
| Description: | This assay detects inhibitors of AKT1 (PKBα) kinase activity using Caliper LabChip LC3000. The Caliper off-chip incubation mobility shift assay uses a microfluidic chip to measure the conversion of a fluorescent labelled peptide to a phosphorylated product by a respective kinase. The complete enzyme reaction is carried out in microtitre plates and then quenched. The resulting stopped solutions are serially "sipped" through a capillary onto the chip, where the peptide substrate and phosphorylated product are separated by electrophoresis. They are then detected via laser-induced fluorescence. Substrate and product are separated into two peaks by the application of a high electric field and directly detected using fluorescence. The signature of the fluorescent signal reveals the extent of the reaction.For Echo dosing the solvent was 100% DMSO. A master plate was prepared with 40 ul of 10 mM stock from our Primary Liquid Store in quadrant 1 of a Labcyte 384 well plate. A 1 in 100 dilution was made from quadrant 1 into quadrant 2 by removing 0.4 ul and adding it to 39.6 ul of DMSO. Subsequent 1 in 100 dilutions were made into quadrant 3 from quadrant 2 and quadrant 4 from quadrant 3. Multiple 2.5 nl droplets were dispensed from each quadrant of the master plate using ECHO dosing technology (Labcyte Inc. Sunnyvale, Calif., USA) to generate the dose range that was required in the test. The dose range most commonly used was as follows: 100 uM, 30 uM, 10 uM, 3 uM, 1 uM, 0.3 uM, 0.1 uM, 0.03 uM, 0.01 uM, 0.003 uM, 0.001 uM, 0.0001 uM. Each well was backfilled with Dimethyl Sulphoxide (DMSO) to a total volume of 120 nl, such that when the enzyme and substrate mix was added the final DMSO concentration was 1%. DMSO was added to max control wells as 120 nl, minimum control wells were treated with 120 nl of compound at a concentration that inhibited the enzyme activity 100%. Following addition of compound or control to the assay plate, 6 ul peptide mix containing 3 uM substrate (5-FAM-GRPRTSSFAEG-CONH2; CRB) and 40 uM ATP in Kinase base buffer (100 mM Hepes pH 7.5, 0.015% Brij-35) and 6 ul enzyme mix containing 8 nM AKT1/PKBα active enzyme (Upstate Biotechnology, Cat No. 14-276), 8 mM DTT and 20 mM MgCl2 in kinase base buffer was added. All buffers were made up with 18M water. The plates were sealed and incubated at room temperature for 50 minutes. The reaction was stopped by the addition of 10 ul stop buffer (100 mM Hepes pH 7.5, 0.015% Brij-35 solution, 0.1% coating reagent #3, 40 mM EDTA, 5% DMSO) to each well (N.B. plates can be frozen after stopping and read later). The plates were then analysed using the Caliper LabChip LC3000 Drug Discovery System (Caliper Life Sciences, 1 Wellfield, Preston Brook, Runcorn, WA7 3AZ) using the following separation conditions; -1.8 PSI, -500 upstream voltage, -1700 downstream voltage, sample sip time of 0.2 sec, post sample sip time of 30 sec and a final delay of 120 sec. Integration of the substrate and product peaks was carried out using Caliper LabChip software and IC50 curves were calculated using Origin software (OriginLab Corporation, Northampton, Mass., USA). |
| Affinity data for this assay | |
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