| Assay Method Information | |
| | LRRK2 Km ATP LanthaScreen Assay |
| Description: | IC50 (half-maximal inhibitory concentration) represents the concentration of inhibitor required to inhibit LRRK2 kinase activity by 50%. Assays were performed in the presence of 134 uM ATP (Km ATP). Upon completion, the assay was stopped, and phosphorylated substrate detected with a terbium (Tb)-labeled anti-pERM antibody (cat. no. PV4898). The compound dose response was prepared by diluting a 10 mM stock of compound to a maximum concentration of 9.99 uM in 100% DMSO, followed by custom fold serial dilution in DMSO nine times. 20 nL of each dilution was spotted via a Labcyte Echo onto a 384-well black-sided plate (Corning 3575) followed by 15 uL of a 1.25 nM enzyme solution in 1 assay buffer (50 mM Tris pH 8.5, 10 mM MgCl2, 0.01% Brij-35, 1 mM EGTA, 2 mM dithiothreitol, 0.05 mM sodium orthovanadate). Following a 15-min incubation period at rt, the kinase reaction was started with the addition of 5 uL of 400 nM fluorescein-labeled LRRKtide (LRRK2 phosphorylated ezrin/radixin/moesin (ERM)) peptide substrate and 134 uM ATP solution in 1 assay buffer. The reaction was allowed to progress at ambient temperature for 90 min. The reaction was then stopped by the addition of 20 uL of TR-FRET Dilution Buffer (Life Technologies, Carlsbad, CA) containing 2 nM Tb-labeled anti-phospho LRRKtide (LRRK2 phosphorylated ezrin/radixin/moesin (ERM)) antibody and 10 mM EDTA (Life Technologies, Carlsbad, CA). After an incubation period of 1 h at rt, the plate was read on an EnVision multimode plate reader (Perkin Elmer, Waltham, MA) with an excitation wavelength of 337 nm (Laser) and a reading emission at both 520 and 495 nm. Compound IC50 values were interpolated from nonlinear regression best-fits of the log of the final compound concentration, plotted as a function of the 520/495-nm emission ratio using activity base Abase ). Abase uses a 4 parameter (4P) logistic fit based on the Levenberg-Marquardt algorithm. |
| Affinity data for this assay | |
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