ChemiSCREEN Membrane Preparation Recombinant Human NOP Opioid Receptor

Human NOP / ORL1 / OP4 GPCR membrane preparation for Radioligand binding Assays & GTPγS binding.

Pricing and availability is not currently available.

Quality Level

biological source



expressed in Chem-1 cells

mfr. no.



ligand binding assay: suitable (GTPγS)
radioligand binding assay (RLBA): suitable

UniProt accession no.

shipped in

dry ice

General description

Full-length human OPRL1 cDNA encoding NOP
The NOP receptor (also known as ORL1) is related to the opioid receptor family of GPCRs but does not bind to classical opioids. An endogenous ligand for NOP has been characterized and termed orphanin FQ or nociceptin (OFQ/N), which in turn does not bind to other members of the opioid receptor family. NOP is expressed widely in the CNS, and binding of OFQ/N to NOP1 appears to function in nociception, locomotor activity, anxiety, reward, memory and tolerance to classical opioids (Mogil and Pasternak, 2001). Millipore′s NOP membrane preparations are crude membrane preparations made from our proprietary stable recombinant cell lines to ensure high-level of GPCR surface expression; thus, they are ideal HTS tools for screening of agonists and antagonists of NOP. The membrane preparations exhibit a Kd of 0.06 nM for 125II-Nociceptin. With 0.1 nM 125I-Nociceptin, 5μg/well NOP Membrane Prep typically yields greater than 10-fold signal-to-background ratio.


Radioligand binding assay and GTPγS binding

Biochem/physiol Actions

Target Sub-Family: Opioid
GPCR Class: A
Protein Target: NOP / ORL1 / OP4


Table 1. Signal:background and specific binding values obtained in a competition binding assay with NOP Receptor membrane prep.
5 µg/well
Signal:Background 23.8
Specific Binding (cpm) 6656

SPECIFICATIONS: 1 unit = 5 µg
Bmax for 125I-Nociceptin binding: 1.1 pmol/mg protein
Kd for 125I-Nociceptin binding: ~0.06 nM


Inucbation Conditions
Membranes are mixed with radioactive ligand and unlabeled competitor (see Figures 1 and 2 for concentrations tested) in binding buffer in a nonbinding 96-well plate, and incubated for 1-2 h. Prior to filtration, an FC 96-well harvest plate (Millipore cat. # MAHF C1H) is coated with 0.33% polyethyleneimine for 30 min, then washed with 50 mM Tris-HCl, pH 7.4. Binding reaction is transferred to the filter plate, and washed 3 times (1 mL per well per wash) with Wash Buffer. The plate is dried and counted.

Binding buffer: 50 mM Tris-HCl, pH 7.4 filtered and stored at 4°C

Radioligand: 125I-Nociceptin. (Perkin Elmer#:NEX-324 )

Wash Buffer: 50 mM Hepes, pH 7.4, 500 mM NaCl , 0.1% BSA, filtered and stored at 4°C.

One package contains enough membranes for at least 200 assays (units), where a unit is the amount of membrane that will yield greater than 10-fold signal:background with 125I labeled Nociceptin

Physical form

Liquid in packaging buffer: 50 mM Tris pH 7.4, 10% glycerol and 1% BSA with no preservatives.
Packaging method: Membranes protein were adjusted to the indicated concentration in 1 ml packaging buffer, rapidly frozen, and stored at -80°C

Storage and Stability

Maintain frozen at –70°C up to the expiration date indicated on the product label. Do not freeze and thaw.

Legal Information

CHEMICON is a registered trademark of Merck KGaA, Darmstadt, Germany


Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

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