## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: Ki
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Determination of Binding Affinity for CGRP Receptor by Radioligand Binding Assay in SK-N-MC Cell Membranes: The binding affinity assay of compounds for human CGRP receptor was carried out by inhibition of radiolabeled ligand [125I]-CGRP binding in human neuroblastoma cell line SK-N-MC cell membranes.Cell membranes prepared from SK-N-MC cells expressing CGRP receptors endogenously (Muff et al., Ann N Y Acad Sci. 1992; 657: 106-116) were used for radioligand binding assay. Radioligand binding assay was performed using 96-well microplate in a total volume of 200 μL in each well. A 2.5 μL of serial dilution of compound dissolved in dimethylsulfoxide (DMSO) was mixed with SK-N-MC cell membranes (40 μg membrane protein per well) and [125I]-CGRP (PerkinElmer NEX354, final concentration of 150 pM) in an assay buffer consisting of 50 mM Tris-HCl, 5 mM MgCl2 and 0.1% bovine serum albumin (pH 7.4). The assay plate was incubated with shaking on a plate shaker at room temperature for 90 minutes. The incubation was terminated by filtration through a GF/C glass fiber filter plate (Merck Millipore) pre-soaked with 0.3% polyethyleneimine (PEI). Filters were washed 4 times with 300 μL of ice-cold assay buffer. After drying the filter plate, 100 μL of scintillation fluid (PerkinElmer, MicroScint-20) was added to each well and the radioactivity was counted using a TopCount NXT (PerkinElmer). Non-specific binding was determined in the presence of 1.25 μM unlabelled human α-CGRP (Bachem). The radioactivity was converted to the percent of specific binding using the equation below.% ⁢ ⁢ of ⁢ ⁢ specific ⁢ ⁢ binding = ( Y - Y ⁢ ⁢ min ) ( Y ⁢ ⁢ max - Y ⁢ ⁢ min ) × 100 [ Number ⁢ ⁢ 1 ]In the formulae, Y is observed radioactivity, Ymax is total bound activity, and Ymin is non-specific bound activity.From these data, the concentration of compound required for 50% inhibition of radioligand binding (IC50) was determined using Prism (GraphPad Inc.). The IC50 value is then converted to the equilibrium dissociation constant (Ki) using the Cheng-Prusoff equation below (Cheng & Prusoff (1973) Biochem. Pharmacol. 22, 3099-3108).Ki = IC 50 1 + [ L ] Kd [ Number ⁢ ⁢ 2 ]In the formulae, [L] is the concentration of radioligand, Kd is the apparent dissociation constant of the radioligand for the receptor as determined by saturation binding assay with [125I]-CGRP.
- Target name: Calcitonin gene-related peptide type 1 receptor
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: Cc1cc(Oc2ccc(C(=O)N[C@H](C)C(=O)N3[C@H](c4cccc(F)c4)CC[C@@H]3C(C)(F)F)cc2C)c(=O)[nH]n1
- Properties:
- ChEMBL ID: CHEMBL5971588
- Molecular weight: 542.56
- Heavy atoms: 39
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 5
- TPSA: 104.39
- LogP: 4.82
- Rotatable bonds: 7
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.36
- QED: 0.45

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 9.89
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type Ki; relation =; value 0.13; units nM; pChEMBL 9.89; comment 1031022

## Query Molecule B
- Canonical SMILES: Cc1cc(Oc2c(C)cc(C(=O)N[C@H](C)C(=O)N3[C@H](c4cccc(Cl)c4)CC[C@@H]3C(C)(C)C#N)cc2F)c(=O)[nH]n1
- Properties:
- ChEMBL ID: CHEMBL5810695
- Molecular weight: 580.06
- Heavy atoms: 41
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 6
- TPSA: 128.18
- LogP: 5.37
- Rotatable bonds: 7
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.37
- QED: 0.39

## Molecule Similarity
- Weighted Tanimoto: 0.66

Answer: 10.15