Secondary Concentration-Response Assay for Activators of Human Liver Pyruvate Kinase: for Probe SAR
Matthew G. Vander Heiden, M.D., Ph.D. [Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115] ..more
NIH Chemical Genomics Center [NCGC]
Matthew G. Vander Heiden, M.D., Ph.D. [Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115]
NCGC Assay Overview:
Human pyruvate kinase liver (hPK-L) enzyme was supplied as a highly purified (>95% pure) preparation from Harvard Medical School and assayed for its ability to generate ATP from ADP using phosphoenolpyruvate (PEP) as a substrate. ATP generation was detected in a coupled reaction by luciferase-mediated luminescence, an ATP-dependent process. Pyruvate kinase substrates, PEP and ADP, were present in the assay at Km and approximately 10-fold below Km respectively. The enzyme was assayed at an intermediate level of activity to screen for both inhibitors and activators.
NCGC Assay Protocol Summary for L-isoform:
Three uL of substrate mix (at r.t.) in assay buffer (50 mM Imidazole pH7.2, 50 mM KCl, 7 mM MgCl2, 0.01% Tween 20, 0.05% BSA) was dispensed into white solid bottom 1,536 well microtiter plates so that the final concentrations of substrates in the assay were 0.1 mM ADP and 0.5 mM PEP. 23 nL of compound were delivered by a pin tool and 1 uL of enzyme mix (final concentration of 0.1 nM) in assay buffer (4 degree Celsius) was added. Plates were incubated at room temperature for 1 hour. Two uL of detection mix (Kinase-Glo, Promega; at 4 degree Celsius protected from light) was added and luminescence read by a ViewLux (Perkin Elmer) at 1 second exposure/plate. Data were normalized to the uninhibited (row 31). Additionally, a no enzyme and 5-fold enzyme control was dispensed in row 32, split equally between the two conditions.
1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent activators are ranked higher than compounds that showed apparent inhibition.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.
* Activity Concentration. ** Test Concentration.
Data Table (Concise)