## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: EC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Cell Based Assay: Ca2+ signaling studies were performed using a FLIPR TETRA system (Molecular Devices, Sunnyvale, Calif., USA) in the 384-format. This is a high-throughput instrument for cell-based assays to monitor Ca2+ signaling associated with GPCRs and ion channels. Cells were seeded at a density of 5×104 cells/well in BioCoat poly-D-lysine coated, black wall, clear bottom 384-well plates (BD Biosciences, Franklin lakes, NJ, USA) and allowed to attach overnight in an incubator at 37° C. The cells were then washed twice with HBSS-HEPES buffer (Hanks' balanced salt solution without bicarbonate and phenol red, 20 mM HEPES, pH 7.4) using an ELx405 Select CW Microplate Washer (BioTek, Winooski, Vt., USA). After 60 min of dye-loading in the dark using the Ca2+-sensitive dye Fluo-4AM (Invitrogen, Carlsbad, Calif., USA), at a final concentration of 2×10^−6M, the plates were washed 4 times with HBSS-HEPES buffer to remove excess dye and leaving 50 μl of buffer in each well. The plates were then placed in the FLIPR TETRA instrument and allowed to equilibrate at 37° C. AGN-211377 was added in a 25 μl volume to each well to give final concentrations of 0.1 μM, 0.3 μM, 1 μM, 3 μM, 10 μM, and 30 μM; or 0.07 μM, 0.1 μM, 0.2 μM, 0.3 μM, 0.67 μM, and 1 μM for cells over-expressing TP receptors. After 4.5 minutes, a 7-point serial dilution of the standard agonist for the corresponding receptor, in a 25 μl volume was injected at the final concentrations from 10^−11M to 10^−5M in 10-fold serial dilution increments for cells expressing human recombinant DP1, EP1, EP2, EP3, EP4, FP, and IP receptors. The dose range for the standard agonist for human recombinant TP receptors was from 10^−12M to 10^−6M. HBSS-HEPES buffer was used as the negative control for the standard agonists. Cells were excited with LED (light emitting diode) excitation at 470-495 nm and emission was measured through an emission filter at 515-575 nm. Assay plates were read for 3.5 minutes using the FLIPRTETRA.
- Target name: Prostaglandin D2 receptor
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: O=C(CCc1ccc(Cl)cc1CN1CCC[C@H]1c1nc(C(=O)NCCCCC2CCCCC2)co1)NS(=O)(=O)C(F)(F)F
- Properties:
- ChEMBL ID: CHEMBL3942394
- Molecule type: Small molecule
- Molecular weight: 647.16
- Heavy atoms: 43
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 7
- TPSA: 121.61
- LogP: 6.04
- Rotatable bonds: 13
- Ring count: 4
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.62
- QED: 0.25

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 7.77
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type EC50; relation =; value 17; units nM; pChEMBL 7.77; comment 315369

## Query Molecule B
- Canonical SMILES: O=C(CCc1cc2c(cc1CN1CCC[C@H]1c1nc(C(=O)NCCCCC3CCCCC3)co1)OCO2)NS(=O)(=O)C(F)(F)F
- Properties:
- ChEMBL ID: CHEMBL3967284
- Molecule type: Small molecule
- Molecular weight: 656.72
- Heavy atoms: 45
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 9
- TPSA: 140.07
- LogP: 5.12
- Rotatable bonds: 13
- Ring count: 5
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.63
- QED: 0.28

## Molecule Similarity
- Weighted Tanimoto: 0.81

Answer: 8.52