Transcreener® GDP GTPase Assays
The Transcreener® GDP GTPase Assay Kit directly measures GDP produced during GTP hydrolysis in a homogeneous mix‑and‑read format—no coupling enzymes needed. Compatible with GTPases, GAPs, and GEFs, it supports FP, FI, and TR‑FRET readouts using far‑red tracers to reduce interference. HTS‑ready with excellent sensitivity (Z′ ≥ 0.7), it streamlines screening and profiling workflows.
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The Transcreener® GDP Assay is a universal, mix-and-read HTS assay for detecting GDP, the product of GTP hydrolysis. Designed for GTPases, GAPs, and GEFs, it eliminates the need for coupling enzymes and provides sensitive, interference-resistant results for drug discovery and mechanism-of-action studies.
Key Features & Benefits
- Direct GDP Detection – Measures GDP directly with a highly selective antibody, avoiding coupling reactions and reducing false positives.
- Universal Application – Works with small and large GTPases, GTPase-activating proteins (GAPs), and guanine nucleotide exchange factors (GEFs).
- Multiple Detection Modes – Supports Fluorescence Polarization (FP), Fluorescence Intensity (FI), and TR-FRET readouts.
- Far-Red Tracers – Minimize compound interference and deliver cleaner data in screening libraries.
- HTS Ready – Validated in 96-, 384-, and 1536-well plate formats with robust performance (Z’ ≥ 0.7).
- Automation Compatible – Homogeneous, mix-and-read format with stable signal for streamlined high-throughput workflows.
Applications
- High-throughput screening (HTS) of GTPase inhibitors
- Profiling GAP and GEF activity
- Mechanism of action and selectivity studies
- Hit-to-lead optimization and triage with reduced assay artifacts
Using the Tristar2 S LB 942 for High-Performance Time-Resolved FRET Analysis
This application note describes the validation of the Tristar2 S LB 942 Multidetection microplate reader with the Transcreener® GDP TR-FRET Red assay from BellBrook Labs. The TriStar2 S combines the user friendliness of a multimodal optical system, with the sensitivity and performance of a dedicated optical device. It has been developed for full modularity and equipped with the proprietary ONE-4-ALL optical system.
Using the Mithras LB 943 for High-Performance Time-Resolved FRET Analysis
This application note describes the validation of the Mithras2 LB 943 Monochromator Multimode reader with the Transcreener® GDP TR-FRET Red assay from BellBrook Labs. The Mithras² LB 943 is a high-end microplate multimode reader based on monochromator technology with excellent performance. Characterized by its sensitivity and robustness, especially in luminescence and BRET measurements, the reader supports all important reading technologies.
Transcreener® High Throughput Screening Assays for Glycosyltransferases
Identifying glycosyltransferase inhibitors remains a challenging task in drug discovery, because for many enzymes in this diverse class, screening methods have been limited to expensive and cumbersome radiolabeled assays or HPLC/MS analyses. As shown here, over the last few years Transcreener® glyscosyltransferase assays have been developed based on the simple and direct immunodetection of nucleotides, which are easily adaptable to automation and systemized high throughput screening protocols.
Investigation of Different GTPase Classes with the Transcreener ® GDP Assay
The Transcreener® GDP Assays are single step, homogenous, fluorescent assays for direct detection and screening of GTPases. Available with fluorescence polarization (FP) and fluorescence intensity (FI) readouts, they provide a safe, HTS-compatible alternative to cumbersome radioassay methods and are more sensitive and less subject to interference than colorimetric phosphate detection methods. This application note shows enzyme data for various classes of GTPases. RGScreen uses kinetically altered Gα subunits of heterotrimeric G proteins in combination with the Transcreener® GDP Assay to provide a robust HTS method for identifying inhibitors of RGS protein GAP activity: from initial screen to profiling hits.
Screening Diverse Glycosyltransferases Using Homogenous, Fluorescent Transcreener HTS Assays for Direct Detection of Nucleotide Products
Glycosyltransferase enzymes participate in extremely diverse metabolic and regulatory roles by catalyzing the transfer of sugar molecules to protein, lipid and carbohydrate acceptors as well as endogenous and xenobiotic small molecules. From a drug discovery point of view, they are gaining increasing interest as targets for “substrate reduction therapy” in lysosomal storage diseases, and as anti-microbial targets for disrupting bacterial cell wall biosynthesis. This study indicates that a suite of Transcreener assays may be a powerful approach for screening and profiling diverse glycosyltransferases in humans.
High Throughput GEF Assay using the Transcreener GDP Assay
This application note serves as a guide for using the Transcreener® GDP Assay to detect the activity of guanine nucleotide exchange factors (GEFs) based on their stimulation of steady state GTPase activity. As an example, an assay was developed using Dbs, a Rho-specific guanine nucleotide exchange factor (RhoGEF) in combination with two monomeric GTPases, CDC42 and RhoA.
TR-FRET readout now available with the Transcreener cGAMP cGAS Assay
With this addition, researchers can more easily screen for small molecule modulators of cGAS
