Ligand Binding Assay Services

Creative Biolabs is the market leader for GPCR ligand binding assay, especially radioligand binding assays. To ensure data repeatability and control for the quality of these crucial reagents, our assays are conducted with membrane preparations.

Ligand binding assays are critical for pharmacological structure-activity studies and basic GPCR research because they provide sensitive and quantitative information regarding guanine nucleotide protein G protein-coupled receptor (GPCR) expression and affinity for a wide range of ligands. They offer a direct assessment of GPCR proteins' interactions with their physiological ligands, as well as medicines and synthetic ligands used for therapeutic purposes or to explore receptor or ligand activity. Binding assays give quantitative information about receptor expression and receptor affinity for practically any ligand, notwithstanding their inability to discriminate agonists from antagonists or inverse agonists. As a result, they're critical for understanding GPCR biochemistry and are crucial components of drug structure-activity research.

Fig.1. Saturation receptor-radioligand binding curve. (Flanagan, 2016)

Considerations for Ligand Binding Assays

• Receptor preparation

Receptor binding assay is a cell-free method theoretically suitable for any GPCR screening without involving downstream signaling from the receptor. Our assays are conducted with membrane preparations. The membrane preparations were prepared in advance and aliquoted and stored at -80 ℃ to save preparation time.

• Radioligand

Because the radioligand supplies the "signal" that is assessed in GPCR-ligand binding assays, the ligand and its label have a significant impact on the assay. Tritium (³H) and ¹²⁵iodine (¹²⁵I) are the most often utilized radioisotopes, while ¹⁴carbon, ³⁵sulfur, and ³²phosphorous may also be used.

• Buffer

Binding test buffers can be selected to simulate in vivo binding circumstances, such as physiological salt solutions or cell culture medium, or they may be optimized for maximal radioligand binding.

• Incubation

The binding assay incubation time and temperature are intimately intertwined. Temperature can alter the stability of the receptor and ligand, as well as the repeatability of the experiment. Radioligand binding may be optimized by incubation at low (4 ℃) or high (37 ℃) temperatures.

Our Feature Service

• Gold standard filtration assays.
• Single concentration screening or dose-response for IC₅₀ determinations.
• One-stop service to provide ligand binding assays.
• Majority of membrane preparations produced in-house.
• Capacity of >10 scintillation counters.
• Assays available using either radiolabeled antagonists or agonists.
• Quick turnaround times of 1-3 weeks depending on project types.

Scientists in Creative Biolabs explored and optimized the GPCR assay. We can offer three types of radioligand binding assay: competitive, saturation and kinetic. Please contact us to discuss your project and we will design a binding assay tailored to achieve your objectives.

Reference

1. Flanagan, C.A. GPCR-radioligand binding assays. Methods in cell biology. 2016; 132: 191-215.