HTRF is a homogenous assay that combines fluorescence resonance energy transfer technology (FRET) with time-resolved measurement (TR). It is one of the most frequently used methodologies for drug target studies in high-throughput screening (HTS). In FRET assays, a signal is generated through fluorescent resonance energy transfer between a donor and an acceptor fluorophore when in close proximity one to each other.
FRET can be combined with TR measurements if lanthanides are used as donors, since they show long emission lifetimes allowing for a time delay of the signal detection between the excitation of the donor and the fluorescence of the acceptor fluorophore. For its unique features, in TR-FRET experiments, buffer and media interference is dramatically reduced. HTRF assay sensitivity and robustness make it appropriate for miniaturization in 384 and 1536-well plate formats.

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LUXendin645 glucagon-like peptide-1 receptor (GLP1R) fluorescent antagonist (645/664) (CELT-112)
View moreOur GLP1R fluorescent antagonist shows high affinity for glucagon-like peptide-1 receptor (pEC50 = 7.5 for GLP1R) modulating the receptor by orthosteric antagonism. The efficacy and potency of LUXendin645 (CELT-112) as a GLP1R ligand was confirmed by inhibition of GLP-1-stimulated cAMP levels in SNAP-GLP1R:HEK293 cells. LUXendin645 (CELT-112) has been used in a variety of imaging applications, including widefield/confocal/2-photon microscopy in live and fixed mammalian cells and tissue. Using TR-FRET, LUXendin645 was used in GLP1R competitive binding experiments and in GLP1R trafficking and recycling studies.
*2º Image: Widefield image of live CHO-K1:SNAP-GLP1R cells labeled with 200 nM LUXendin645. Scale bar = 40 micrometer.More information and applications
https://www.nature.com/articles/s41467-020-14309-w
https://pubmed.ncbi.nlm.nih.gov/34129856/
https://molpharm.aspetjournals.org/content/early/2021/07/27/molpharm.121.000270
https://pubs.acs.org/doi/10.1021/acsptsci.0c00022 -
CELT-335 hCB1/CB2 Cannabinoids receptors fluorescent ligand (646/662)
View moreOur potent hCB cannabinoids receptors fluorescent ligand shows high affinity for hCB1/CB2 cannabinoids receptor (Ki =44.8 nM and 7.4 nM , respectively in radioligand binding assay). It has been validated in High Content Screening assays and it is suitable also for HTRF binding assays as a valid alternative to radioligand binding assays. It allows to perform cell visualization in fluorescence microscopy and it is potentially suitable for other fluorescence-based assays.
More information and applications
https://www.sciencedirect.com/science/article/pii/S1043661821005545?via%3Dihub