Homogenous Transcreener UDP2 TR-FRET Assay for High Throughput Screening with Glycosyltransferases

Transcreener UDP2 Assay - TR-FRET Readout

The Transcreener® UDP2 Assay with TR-FRET readout uses displacement of a tracer by UDP to measure enzymatic activity. This disrupts FRET from the antibody-bound Terbium chelate leading to a decrease in the TR-FRET signal. In addition to the time-resolved signal, the assay uses a far-red tracer to minimize interference from fluorescent compounds and light scattering.

The assay produces an excellent signal at low substrate conversion for a broad range of initial UDP-sugar donor concentrations (1 - 1,000 µM). Both reagents & signal are stable at room temperature for over 24 hours, providing outstanding flexibility for automated high-volume screening programs. The universal detection method allows screening of virtually any glycosyltransferase in a high throughput format.

Used in over millions of well by pharma since 2006, Transcreener is the most extensively validated UDP 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 UDP to Measure Glycosyltransferase Enzymatic Activity

Time-Resolved Förster Resonance Energy Transfer (TR-FRET)

UDP Assay Schematic - TR-FRET Readout


  • Measure Enzymatic Activity of Glycosyltransferases
  • Screen Compound Libraries for Glycosyltransferase Modulators
  • Quantify Inhibitor Potency
  • Inhibitor Selectivity Profiling
  • Measure Drug-Target Residence Time


  • Direct detection of unlabeled UDP
  • Robust Assay Z' > 0.7 under initial velocity conditions
  • Far-red fluorescent readouts minimize compound interference
  • A safe, non-radioactive method
  • Use with UDP-sugar donor concentrations from 1 to 1000 µM
  • Universal - use with virtually any glycosyltransferase

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

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


Example Applications

The Transcreener UDP Assay is compatible with any enzyme class that produces UDP, including UDP-glucose-, UDP-galactose-, & UDP-glucuronosyl-transferases-, as well as glycogen, hyaluranon, & cellulose synthetases.

Toxin B

Far Red TR-FRET Readouts Validated on Major Multimode Readers

SupplierInstrumentTR-FRET Assays
TriStar2S LB 942Click Me ArrowValidated
Tristar 5In Review
Mithras2 LB 943Click Me ArrowValidated
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® OmegaClick Me ArrowValidated
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® 3Click Me ArrowValidated
SpectraMax® ParadigmClick Me ArrowContact Us
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
  • Z' specifications to be met using Transcreener ADP2 Assay Reagents
  • Read time to achieve Z' specifications in ≤ 5 minutes

Look for these validation 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 the 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. 

Transcreener Instrument Validation

What's Included

What You Will Need

Transcreener UDP2 Assay Kits - TR-FRET Readout

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

Assay Plates for TR-FRET