Targeting LRRK2 for Parkinson's Disease with the Transcreener® GDP GTPase Assay

Transcreener GDP Assay Kit - FP Readout

The Transcreener GDP Assay with FP readout measures GDP via antibodies selective to GDP and a far-red fluorescent tracer. GDP produced in the reaction competes with the tracer, decreasing fluorescent properties and providing a fluorescent readout. The universal detection method allows screening of virtually any kinase in a high throughput format.

The Transcreener Assay offers reagent stability and compatibility with commonly used multimode plate readers. The FP GDP Assay accommodates GTP concentrations ranging from 1 µM to 1,000 µM with excellent data quality (Z' ≥ 0.7) at low substrate conversion (typically 10-30%).

Used in over millions of wells by pharma since 2006, Transcreener is the most extensively validated GDP detection method available backed by the best technical support in the industry.

This assay is designed to be used with purified enzyme preparations. Transcreener assays are not validated with cell lysates, blood, serum, or other biological samples.

Direct Detection of GDP to Measure GTPase Enzymatic Activity

Fluorescence Polarization (FP)

GDP Assay Kit - FP Readout v2


  • Measure enzymatic activity of GTPases
  • Screen compound libraries for GTPase Modulators
  • Quantify Inhibitor Potency
  • Inhibitor Selectivity Profiling
  • Measure Drug-Target Residence Time


  • Direct Detection of unlabeled GDP
  • Robust Assay Z' > 0.7 under initial velocity conditions
  • Far-red fluorescent readouts minimize compound interference
  • A safe, non-radioactive method
  • Use with GTP concentrations from 1 µM to 1,000 µM
  • Stable Assay reagents - minimum 8-hour reagent and signal stability even at room temperature!

Easy-to-Use, Mix-&-Read, HTS Ready

Run your enzyme reaction, add Transcreener reagents, and read your plates. The GDP assay is compatible with 96, 384, and 1536-well formats. 

GDP GTPase Assay Schematic

Example Applications

GTPase FamilyEnzyme
Ras FamilyKRAS
Rho FamilyRhoA
Ran FamilyRan

Detection of GDP Released by KRAS (FP Readout)

Below is an example of the Transcreener GDP Assay with FP readout detecting GDP released by the GTPase, KRAS. The assay demonstrates linearity when raw data is converted to GDP using a standard curve.

KRAS Enzyme Titration

KRAS Assay Enzyme Titration Curve Concentration Dependence

Linear Response

KRAS Linear Response Curve Concentration Dependence

Far Red FP Readouts Validated on Major Multimode Readers

SupplierInstrumentFP Assays
TriStar2S LB 942In Review
Tristar 5In Review
Mithras2 LB 943In Review
CytationTM 5Validated
CytationTM 3Validated
CytationTM 1Validated
SynergyTM H1Validated
SynergyTM 2/H4/4Click Me ArrowValidated
SynergyTM HTXNot Capable
SynergyTM Neo 2Validated
POLARstar® OmegaClick Me ArrowValidated
FLUOstar® OmegaNot Capable
PHERAstar® FSXClick Me ArrowValidated
PHERAstar® Plus/FSClick Me ArrowValidated
CLARIOstar® /PlusClick Me ArrowValidated
VANTAstarTMClick Me ArrowValidated
SenseIn Review
Analyst® GT/HTClick Me ArrowValidated
Gemini® XPS/EMNot Capable
SpectraMax® M2/M2eNot Capable
SpectraMax® M5/M5e/FlexStation® 3Not Capable
SpectraMax® ParadigmClick Me ArrowValidated
SpectraMax® iD3/iD5Click Me ArrowValidated
SpectraMax® i3xClick Me ArrowValidated
EnVision®/EnVision® XciteClick Me ArrowValidated
Infinite® M1000/M1000Pro/Safire2TMClick Me ArrowValidated
Infinite® M200Not Capable
Infinite® F500Click Me ArrowValidated
Infinite® F200/UltraevolutionClick Me ArrowContact Us
SparkTM 10MClick Me ArrowValidated

Validation Criteria for Plate Readers

  • 384-Well Format
  • Z'-Factor ≥ 0.7 at 10% conversion of 10 μM ATP
  • Δ mP ≥ 95 mP at 10% conversion of 10 μM ATP
  • Z' and Δ mP specifications to be met using Transcreener ADP2 Assay Reagents
  • Read time to achieve Z' and Δ mP specifications ≤ 5 minutes

Look for these stickers on instruments that have successfully met the validation criteria.

The instrument validation program is a collaborative effort with the major suppliers of multimode readers to insure that Transcreener assays perform optimally on your specific instrument. Scientists at Bellbrook and/or instrument vendor have tested Transcreener reagents with each instrument to determine optimal filters and settings for maximal assay performance. We provide you with application notes with all the important details, so you can be confident of success using Transcreener assays on the instrument of your choice. 

What's Included

What You Will Need

Transcreener GDP Assay Kits - FP Readout

*For custom or bulk orders (over 100,000 wells), please contact us (info@bellbrooklabs.com) for a quote.

Assay Plates for FP