## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: EC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: cAMP ASSAY: The activation of the SSTR4 receptor (Gi coupled) causes an inhibition of intracellular cAMP after stimulation with Forskolin, which can be quantifiable by use of a suitable assay Kit and an adequate plate reader. This technique is used to characterize pharmacological effects of the SSTR4 receptor agonists by use of hSSTR4 expressing H4 cells.Compounds are dissolved and diluted in DMSO. The final test solution contains 1 DMSO. The cAMP standard (Lance cAMP 384 Kit; PerkinElmer, Cat #AD0264) is prepared in assay buffer (HBSS with 0.1% BSA, 5 mM HEPES, 0.5 M IBMX, pH 7.4) containing 1% DMSO and the cAMP standard curve is included at least on one plate. Cells are centrifuged and suspended in assay buffer (incl. 1:100 diluted Alexa antibody).For the assay 5 μl of a cell suspension (approximately 5000 cells/well) incl. Alexa antibody (diluted 1:100) are added into a 384 well MTP microtitre plate excepting one row or column (depending on the plate layout), which is reserved for the standard curve. Then 2 μl of compound sample is added as concentration response curve (e.g. 1e-5 M to 6e-10 M), usually in triplicates. Each assay contains incubations with vehicle controls instead of compound as controls for non-inhibited cAMP generation (100% CTL; high values) and incubations with 1 μM Somatosatin as controls for full inhibition and background (0% CTL; low values). After approximately 10-15 min incubation time 3 μl Forskolin (dissolved in DMSO, final conc. 15 μM) is added. Then the plates are shaken briefly and incubated for 60 min at room temperature. After 60 min 10 μl of the detection mix is added into all wells followed by an additional incubation period of 1 h. The plates are read in a suitable plate reader.The analysis of the data is based on the ratio of the time-resolved fluorescence measurements of donor and acceptor fluorophore (Ex: 320 nm; Em1: 665 nm; Em2: 615 nm; ratio 665/615). From this ratio, cAMP concentrations are calculated from standard curve and the EC50 is estimated by least square curve fit program.
- Target name: Somatostatin receptor type 4
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: Cn1nc(C(C)(C)NC(=O)c2cccc3c2OCCNC3)c2ccc(F)cc21
- Properties:
- ChEMBL ID: CHEMBL6023537
- Molecular weight: 382.44
- Heavy atoms: 28
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 4
- TPSA: 68.18
- LogP: 2.86
- Rotatable bonds: 3
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.33
- QED: 0.73

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 9.05
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type EC50; relation =; value 0.9; units nM; pChEMBL 9.05; comment 633360

## Query Molecule B
- Canonical SMILES: Cc1nnc(C(C)(C)NC(=O)c2cccc3c2OCCNC3)c2ccccc12
- Properties:
- ChEMBL ID: CHEMBL5763916
- Molecular weight: 376.46
- Heavy atoms: 28
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 5
- TPSA: 76.14
- LogP: 3.09
- Rotatable bonds: 3
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.32
- QED: 0.73

## Molecule Similarity
- Weighted Tanimoto: 0.61

Answer: 8.6