Assay Report Card

ID: ALA3887191

Type: Binding

Description: Biological Assay: The compounds of the invention can be tested for their ability to inhibit LSD1. The ability of the compounds of the invention to inhibit LSD1 can be tested as follows. Human recombinant LSD1 protein was purchased from BPS Bioscience Inc (catalog reference number 50100: human recombinant LSD1, GenBank accession no. NM_015013, amino acids 158-end with N-terminal GST tag, MW: 103 kDa). In order to monitor LSD1 enzymatic activity and/or its inhibition rate by our inhibitor(s) of interest, di-methylated H3-K4 peptide (Anaspec) was chosen as a substrate. The demethylase activity was estimated, under aerobic conditions, by measuring the release of H2O2 produced during the catalytic process, using the Amplex Red hydrogen peroxide/peroxidase assay kit (Invitrogen).Briefly, a fixed amount of LSD1 was incubated on ice for 15 minutes, in the absence and/or in the presence of at least eight 3-fold serial dilutions of the respective inhibitor (e.g., from 0 to 75 uM, depending on the inhibitor strength). Tranylcypromine (Biomol International) was used as a control for inhibition. Within the experiment, each concentration of inhibitor was tested in duplicate. After leaving the enzyme interacting with the inhibitor, KM of di-methylated H3-K4 peptide was added to each reaction and the experiment was left for 30 minutes at 37° C. in the dark. The enzymatic reactions were set up in a 50 mM sodium phosphate, pH 7.4 buffer. At the end of the incubation, Amplex Red reagent and horseradish peroxidase (HPR) solution were added to the reaction according to the recommendations provided by the supplier (Invitrogen), and left to incubate for 5 extra minutes at room temperature in the dark. A 1 uM H2O2 solution was used as a control of the kit efficiency. The conversion of the Amplex Red reagent to resorufin due to the presence of H2O2 in the assay, was monitored by fluorescence (excitation at 540 nm, emission at 590 nm) using a microplate reader (Infinite 200, Tecan). Arbitrary units were used to measure level of H2O2 produced in the absence and/or in the presence of inhibitor. The maximum demethylase activity of LSD1 was obtained in the absence of inhibitor and corrected for background fluorescence in the absence of LSD1. The IC50 value of each inhibitor was calculated with GraphPad Prism Software.