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BioAssay: AID 2100

qHTS Assay for Inhibitors and Activators of Human alpha-Glucosidase Cleavage of Glycogen

Alpha-glucosidase is responsible for the hydrolysis of terminal, non-reducing 1,4-linked alpha-D-glucose residues, which releases alpha-D-glucose. It is a lysosomal hydrolase that is required for the degradation of a small percentage (1-3%) of cellular glycogen in humans. Deficiency of this enzyme results in glycogen-storage disease type II (GSDII), also referred to as Pompe disease, an autosomal more ..
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 Tested Compounds
 Tested Compounds
All(302306)
 
 
Active(1165)
 
 
Inactive(291892)
 
 
Inconclusive(9324)
 
 
 Tested Substances
 Tested Substances
All(304269)
 
 
Active(1169)
 
 
Inactive(293744)
 
 
Inconclusive(9356)
 
 
AID: 2100
Data Source: NCGC (AGLU007)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2009-11-05
Modify Date: 2010-03-30

Data Table ( Complete ):           View Active Data    View All Data
Target
BioActive Compounds: 1165
Related Experiments
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AIDNameTypeProbeComment
1466qHTS Assay for Inhibitors of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe DiseaseConfirmatory depositor-specified cross reference
1473Quantitative High-Throughput Screen for Inhibitors and Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: SummarySummary1 depositor-specified cross reference
2242qHTS Assay for Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe DiseaseConfirmatory depositor-specified cross reference
2293Direct Measure of the Activation of Acid alpha-Glucosidase Catalytic RateOther depositor-specified cross reference
2641qHTS Assay for Inhibitors of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Stabilizers of Alpha-Glucosidase Under Thermal Denaturation ConditionsOther depositor-specified cross reference
1467qHTS Assay for Inhibitors of Human alpha-Galactosidase at pH 4.5.Confirmatory same project related to Summary assay
2101qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher DiseaseConfirmatory same project related to Summary assay
2107qHTS Assay for Inhibitors and Activators of Human alpha-Galactosidase From Spleen HomogenateConfirmatory same project related to Summary assay
2108Confirmation of Inhibitors of Human alpha-Galactosidase Using Spleen HomogenateConfirmatory same project related to Summary assay
2109Confirmation of Inhibitors and Activators of Purified Human alpha-GalactosidaseConfirmatory same project related to Summary assay
2110Confirmation of Inhibitors and Activators of Purified Human alpha-Glucosidase Using an Alternate Red Fluorescent SusbtrateConfirmatory same project related to Summary assay
2111Confirmation of Inhibitors and Activators of Human alpha-Glucosidase From Spleen Homogenate Using an Alternate Red Fluorescent SusbtrateConfirmatory same project related to Summary assay
2112qHTS Assay for Inhibitors and Activators of Human alpha-Glucosidase From Spleen HomogenateConfirmatory same project related to Summary assay
2113Confirmation of Inhibitors and Activators of Human alpha-Glucosidase From Spleen HomogenateConfirmatory same project related to Summary assay
2115Confirmation of Inhibitors and Activators of Purified Human alpha-GlucosidaseConfirmatory same project related to Summary assay
504681Inhibitors of Human alpha-Glucosidase: PBS Stability ProfilingOther same project related to Summary assay
504686Inhibitors of Human alpha-Glucosidase: Caco-2 Cell Permeability ProfilingOther same project related to Summary assay
504688Inhibitors of Human alpha-Glucosidase: Caco-2 Efflux Ratio ProfilingOther same project related to Summary assay
540341Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Glucocerebrosidase Counter ScreenConfirmatory same project related to Summary assay
540361Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Alpha-Galactosidase Counter ScreenConfirmatory same project related to Summary assay
602122qHTS for Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Fibroblast TranslocationOther same project related to Summary assay
602237qHTS for Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Aqueous SolubilityOther same project related to Summary assay
602238qHTS for Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Metabolic StabilityOther same project related to Summary assay
602239qHTS for Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Metabolic Stability in presence of NADPHOther same project related to Summary assay
Description:
NIH Chemical Genomics Center [NCGC]
NIH Molecular Libraries Probe Production Centers Network [MLPCN]

MLPCN Grant: R03 MH084841-01
Assay Submitter (PI): Wei Zheng

NCGC Assay Overview:

Alpha-glucosidase is responsible for the hydrolysis of terminal, non-reducing 1,4-linked alpha-D-glucose residues, which releases alpha-D-glucose. It is a lysosomal hydrolase that is required for the degradation of a small percentage (1-3%) of cellular glycogen in humans. Deficiency of this enzyme results in glycogen-storage disease type II (GSDII), also referred to as Pompe disease, an autosomal recessive disorder. Structurally normal glycogen is accumulated in the lysosomes and cytoplasm in affected patients, primarily in muscle tissues. Excessive glycogen storage within lysosomes may interrupt normal functioning of other organelles and leads to cellular injury. In turn, this leads to enlargement and dysfunction of the entire organ involved (eg: cardiomyopathy and muscle weakness).

It has been reported that the improper folding and trafficking of alpha-glucosidase resulting from genetic mutations may account for a significant number of Pompe patients. 1-deoxynojirimycin, an inhibitor of alpha-glucosidase, was reported to exhibit pharmacological chaperone activity, which significantly increases the mutant enzyme activity in cells. We optimized this alpha-glucosidase assay in 1536-well plate format for identification of novel small molecule inhibitors or activators with structures other than the sugar analogs in order to develop new pharmacological chaperones. Previous assays of alpha-Glucosidase have utilized a non-natural fluorescent substrate to probe enzyme activity. The present assay measures enzyme activity on glycogen using a coupled-assay system to glucose oxidase.
Protocol
NCGC Assay Protocol Summary:

This is an enzyme assay using glycogen from bovine liver (Sigma catalog #: G0885) as the substrate and recombinant human alpha-glucosidase as the enzyme preparation. Upon hydrolysis of the substrate, the glucose product can be detected using the Amplex Red Glucose Oxidase Assay Kit (Invitrogen catalog #: A22189). The product of this reaction can be read with a fluorescence plate reader with an excitation at 573 nm and an emission at 610 nm. Data were normalized to the controls for basal activity (without enzyme) and 100% activity (with enzyme). The AC50 values were determined from concentration-response data modeled with the standard Hill equation.

Assay buffer for enzyme reaction: 50 mM citric acid (titrated with potassium phosphate to pH 5.0), 0.01% Tween-20 (pH 5.0 is an optimal condition for this enzyme assay)

Assay buffer for Amplex Red reaction: Tris-HCl, pH 7.5

1536-well assay protocol for the alpha-glucosidase assay:
(1) Add 2 ul/well alpha-glucosidase enzyme solution (4 nM final)
(2) Add 23 nL compounds in DMSO solution. The final titration was 0.7 nM to 77 uM.
(3) Add 1 ul of glycogen substrate solution (30 ug)
(4) Incubate at 37 C for 40 min
(5) Add 2 ul tris-HCl buffer with Amplex Red reagents
(6) Incubate 45 min at room temperature.
(7) Detect the assay plate in a ViewLux plate reader (PerkinElmer) with Ex=573 nm and Em=610nm.

Keywords: Alpha-glucosidase, Pompe Disease, pharmacological chaperone, chaperone therapy, high throughput screening, alpha-glucosidase inhibitor, MLSMR, MLSCN, NIH Roadmap, qHTS and NCGC
Comment
Compound Ranking:

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 inhibitors are ranked higher than compounds that showed apparent activation.
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.
Result Definitions
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TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1PhenotypeIndicates type of activity observed: inhibitor, activator, fluorescent, cytotoxic, inactive, or inconclusive.String
2Potency*Concentration at which compound exhibits half-maximal efficacy, AC50. Extrapolated AC50s also include the highest efficacy observed and the concentration of compound at which it was observed.FloatμM
3EfficacyMaximal efficacy of compound, reported as a percentage of control. These values are estimated based on fits of the Hill equation to the dose-response curves.Float%
4Analysis CommentAnnotation/notes on a particular compound's data or its analysis.String
5Curve_DescriptionA description of dose-response curve quality. A complete curve has two observed asymptotes; a partial curve may not have attained its second asymptote at the highest concentration tested. High efficacy curves exhibit efficacy greater than 80% of control. Partial efficacies are statistically significant, but below 80% of control.String
6Fit_LogAC50The logarithm of the AC50 from a fit of the data to the Hill equation (calculated based on Molar Units).Float
7Fit_HillSlopeThe Hill slope from a fit of the data to the Hill equation.Float
8Fit_R2R^2 fit value of the curve. Closer to 1.0 equates to better Hill equation fit.Float
9Fit_InfiniteActivityThe asymptotic efficacy from a fit of the data to the Hill equation.Float%
10Fit_ZeroActivityEfficacy at zero concentration of compound from a fit of the data to the Hill equation.Float%
11Fit_CurveClassNumerical encoding of curve description for the fitted Hill equation.Float
12Excluded_PointsWhich dose-response titration points were excluded from analysis based on outlier analysis. Each number represents whether a titration point was (1) or was not (0) excluded, for the titration series going from smallest to highest compound concentrations.String
13Max_ResponseMaximum activity observed for compound (usually at highest concentration tested).Float%
14Activity at 0.122 uM (0.122μM**)% Activity at given concentration.Float%
15Activity at 0.611 uM (0.610998μM**)% Activity at given concentration.Float%
16Activity at 3.051 uM (3.05142μM**)% Activity at given concentration.Float%
17Activity at 15.29 uM (15.2928μM**)% Activity at given concentration.Float%
18Activity at 76.30 uM (76.3μM**)% Activity at given concentration.Float%
19Activity at 76.37 uM (76.374μM**)% Activity at given concentration.Float%
20Compound QCNCGC designation for data stage: 'qHTS', 'qHTS Verification', 'Secondary Profiling'String

* Activity Concentration. ** Test Concentration.
Additional Information
Grant Number: MH084841-01

Data Table (Concise)
Data Table ( Complete ):     View Active Data    View All Data
Classification
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