Compound (SMILES): O=C(O)c1ccc2nc(-c3ccccc3)c(N3CC[C@@H](O)C3)nc2c1
InChIKey: HHMZHNSQCKBNQA-CQSZACIVSA-N
Target: PAS domain-containing serine/threonine-protein kinase (SINGLE PROTEIN), Homo sapiens
UniProt: Q96RG2
Assay: PAS Kinase FRET Assay: The aim of the FRET assay is to determine the inhibition potential of test compounds on targeted kinase. This assay platform provides a homogenous screening method for measuring kinase activity by quantitating the amount of phospho-substrate in solution following a kinase reaction.In the presence of kinase and ATP, the Ulight-peptide is phosphorylated and captured by an anti-phospho-substrate antibody, which brings the Eu chelate donor and Ulight acceptor dyes into close proximity. Upon excitation at 340 nm, the Eu chelate transfers its energy to the Ulight dye, resulting in a fluorescent light emission at 665 nm.Titration of kinase at 1 mM ATP was achieved via the following protocol. After making serial three-fold dilutions of PASK (Invitrogen) in reaction buffer across the plate; 5 μl of kinase dilution and 5 μl substrate/ATP mix were added to the wells of the white Optiplate-384 (PerkinElmer). The contents of the plate were and incubated at RT for 1 h. The reaction was stopped by adding 5 μl of stop solution to each test well followed by mixing and incubation at RT for 10 minutes. 5 μl of detection mix (detection antibody diluted in detection buffer) was added; the contents of the plate were mixed and then incubated in the dark for 1 hour at RT. The signal was recorded at TR-FRET mode (665 nm/615 nm). The results were graphed to calculate the EC50. Titration of ATP at the EC50 concentration of kinase to determine ATP Km,app. was performed using the following method. After making serial dilutions of ATP (Invitrogen), 5 μl of ATP dilution and 5 μl substrate/kinase mix were added to the wells of the white Optiplate-384 (PerkinElmer). The contents of the plate were and incubated at RT for 1 h. The reaction was stopped by adding 5 μl of stop solution to each test well followed by mixing and incubation at RT for 10 minutes. 5 μl of detection mix (detection antibody diluted in detection buffer) was added; the contents of the plate were mixed and then incubated in the dark for 1 hour at RT. The signal was recorded at TR-FRET mode (665 nm/615 nm). The results were graphed to calculate the EC50 as the ATP Km,app.Compound screening was done via the following method. 10 mM stock solution of test compound in DMSO was prepared by dissolving test compound in DMSO at RT for 1 hour, and then sonicating at 100% output for 8 minutes. If compound is not soluble under this condition, it was diluted to 3 mM. Kinase reaction buffer was prepared containing 10 mM MgCl2, 50 mM HEPES, 1 mM EGTA, 0.01% TWEEN-20, 2 mM DTT. Serial dilutions of the test compounds were prepared at 4× final assay concentrations using Freedom EVO200® dispensing system as follows: 12×10−5 M 4×10−5 M, 1.33×10−5 M, 4.44×10−6 M, 1.48×10−6 M, 4.92×10−7 M, 1.65×10−7 M, 5.48×10−7 M, 1.82×10−8 M, 6.09×10−9, 2.03×10−9 M. Test compounds (2.5 μl at 4× the final assay concentration) was added to wells using Freedom EVO200® dispensing system. As a positive control, 2.5 μl of positive compound was added to assay wells, and 2.5 μl of DMSO to assay wells as vehicle control. Kinase solution was prepared in reaction buffer at 2× final assay concentration. Kinase solution (5 μl) was added to each well of the assay plate. The substrate and ATP solution was prepared in kinase reaction buffer at 4× final assay concentration. The kinase reaction was started by adding 2.5 μl of substrate+ATP mix solution to each well of the assay plate. The plate is mixed on a plate shaker; then covered and allowed to react for 2 hours in the dark at 25° C. without shaking. The reaction was stopped by adding 5 μl of stop solution to each test well followed by mixing and incubation at RT for 10 minutes in the dark.
Measurement: IC50 < 10000 nM (pChEMBL 5)
Descriptors: MW 335.36, ALogP 2.57, HBA 5, HBD 2, PSA 86.55, QED 0.76