Assay Method Information

Assay Name:  Biological Activity of Examples 1 to 30
Description:  The inhibitory effects of Examples 1 to 30 on the activity of Human Arginase 1 and Arginase 2 activity were quantified by measuring the formation of the thiol group from thioarginine using recombinant Arginase 1 or Arginase 2 produced from E. coli. The thiol group was detected with Ellman's reagent, 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB). DTNB reacts with the thiol to give the mixed disulfide and 2-nitro-5-thiobenzoic acid (TNB) which is quantified by the absorbance of the anion (TNB2−) at 412 nm.The assays were run in clear 384 well plates (Greiner cat no: 781101). Various concentrations of Examples 1 to 30 in 300 nL DMSO were dispensed to assay plates using an Echo acoustic dispenser immediately followed by plate sealing and centrifugation. Two pre-mixes were prepared from reagents thawed immediately before addition to assay plates. Pre-mix one comprised human Arginase 1 or human Arginase 2, at a final concentration of 5 nM and 0.5 mM DTNB in assay buffer, 45 mM HEPES pH7.5, brij 35, 0.045% (w/v) and 100 μM MnCl2. Pre-mix two comprised freshly thawed 0.5 mM thioarginine in assay buffer. Fifteen microlitres of pre-mix one was dispensed to assay plates containing Examples 1 to 30, centrifuged and incubated for 30 minutes at room temperature prior to adding fifteen microlitres of pre-mix two.Assay plates were centrifuged prior to reading absorbance at 412 nm in a Pherastar multi-mode plate reader to collect data at time point 0 (T0). The plates were incubated at room temperature for 60 min prior to reading again to collect data at time point 1 (T1). Data is derived by subtracting the A412 signal measured at T0 (time point 0) from that measured at T1 (time point 1). The data was transformed to % effect using the equation:Compound % effect=100*[(X−min)/(max−min)], where X represents the normalized value for the compound based on the Min (vehicle) and Max (reference compound) inhibition control.
Affinity data for this assay
 

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