## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: EC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Measurement of Orexin Type 2 Receptor Agonist Activity: Chinese hamster ovary (CHO) dhfr-cells forcibly expressing human orexin type 2 receptor (hOX2R) were seeded in each well of Black clear bottom plate (384 wells) (Becton, Dickinson and Company) by 10,000 cells, and cultured for 16 hr in an MEM-alpha (Nikken-Bio Co., Ltd.) medium containing 100 U/ml penicillin, 100 μg/ml streptomycin, 0.5 g/ml G418 (all above Invitrogen), and 10% fetal calf serum (Thermo), under the conditions of 37° C., 5% CO2. After removal of the medium, 30 μL of assay buffer 1 (0.1% bovine serum albumin (Wako Pure Chemical Industries, Ltd.), 1.25 mM probenecid, 10% B2-Quencher, 2.5 μg/mL Fluo-4AM, 10 mM HEPES (DOJINDO)) was added, and the cells were incubated for 60 min under the conditions of 37° C., 5% CO2. A test compound was dissolved in dimethyl sulfoxide to 10 mM, and then diluted with assay buffer 2 (20 mM HEPES, Hanks' balanced salt solution (Invitrogen), 0.1% bovine serum albumin). For the reaction, a test compound solution (10 μL) was added using Fluorescent Imaging Plate Reader TETRA (FLIPR TETRA; manufactured by Molecular Devices), a fluorescence value (excitation wavelength 488 nm, measurement wavelength 570 nm) of each well was measured every one second for 1 min, and the agonist activity was determined using the area of the fluorescence value as an indicator of intracellular Ca2+ concentration. The agonist activity of the test compound was calculated assuming that the fluorescence value of the well added with only the dilution buffer was 0% and the fluorescence value of the well added with 10 nM human orexin B (PEPTIDE INSTITUTE, INC.) buffer was 100%. The agonist activity values EC50 and Emax of each compound are shown below. As used herein, Emax indicates the value at 30 uM concentration when orexin B is converted to a full agonist (maximum value of agonist activity: 100%).
- Assay organism: Homo sapiens
- Target name: Orexin receptor type 2
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: CN(C)S(=O)(=O)N[C@H]1CCCN(C(=O)OCC(F)(F)F)[C@H]1COC1CCN(c2ncccn2)CC1
- Properties:
- ChEMBL ID: CHEMBL5790987
- Molecular weight: 524.57
- Heavy atoms: 35
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 8
- TPSA: 117.2
- LogP: 1.39
- Rotatable bonds: 8
- Ring count: 3
- Aromatic rings: 1
- Formal charge: 0
- Fraction Csp3: 0.75
- QED: 0.54

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 6.77
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type EC50; relation =; value 170; units nM; pChEMBL 6.77; comment 1155598

## Query Molecule B
- Canonical SMILES: COC(=O)N1CCC[C@H](NS(C)(=O)=O)[C@@H]1CO[C@H]1CC[C@@H](c2ccn(C)n2)CC1
- Properties:
- ChEMBL ID: CHEMBL5819640
- Molecular weight: 428.56
- Heavy atoms: 29
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 6
- TPSA: 102.76
- LogP: 1.61
- Rotatable bonds: 6
- Ring count: 3
- Aromatic rings: 1
- Formal charge: 0
- Fraction Csp3: 0.79
- QED: 0.74

## Molecule Similarity
- Weighted Tanimoto: 0.42

Answer: 5.62