## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: JAK3 Inhibition Assay: Recombinant human JAK3 catalytic domain (amino acids 781-1124; catalog number PV3855) was purchased from Invitrogen. 0.03 mU of JAK3 was incubated with 2.5 μg polyGT substrate (Sigma catalog number P0275) in kinase reaction buffer (25 mM Tris pH 7.5, 0.5 mM EGTA, 0.5 mM Na3VO4, 5 mM b-glycerolphosphate, 0.01% Triton X-100, 1 μM non-radioactive ATP, 0.25 μCi 33P-gamma-ATP (GE Healthcare, catalog number AH9968) final concentrations) with or without 5 μL containing test compound or vehicle (DMSO, 1% final concentration), in a total volume of 25 μL, in a polypropylene 96-well plate (Greiner, V-bottom). After 105 min at 30° C., reactions were stopped by adding of 25 μL/well of 150 mM phosphoric acid. All of the terminated kinase reaction was transferred to prewashed (75 mM phosphoric acid) 96 well filter plates (Perkin Elmer catalog number 6005177) using a cell harvester (Perkin Elmer). Plates were washed 6 times with 300 μL per well of a 75 mM phosphoric acid solution and the bottom of the plates was sealed. 40 μL/well of Microscint-20 was added, the top of the plates was sealed and readout was performed using the Topcount (Perkin Elmer). Kinase activity was calculated by subtracting counts per minute (cpm) obtained in the presence of a positive control inhibitor (10 μM staurosporine) from cpm obtained in the presence of vehicle. The ability of a test compound to inhibit this activity was determined as:Percentage inhibition=((cpm determined for sample with test compound present−cpm determined for sample with positive control inhibitor) divided by (cpm determined in the presence of vehicle−cpm determined for sample with positive control inhibitor))*100.Dose dilution series were prepared for the compounds enabling the testing of dose-response effects in the JAK3 assay and the calculation of the IC50 for each compound. Each compound was routinely tested at concentration of 20 μM followed by a ⅓ serial dilution, 8 points (20 μM-6.67 μM-2.22 μM-740 nM-247 nM-82 nM-27 nM-9 nM) in a final concentration of 1% DMSO. When potency of compound series increased, more dilutions were prepared and/or the top concentration was lowered (e.g. 5 μM, 1 μM).
- Assay organism: Homo sapiens
- Target name: Tyrosine-protein kinase JAK3
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: O=C(Nc1nc2cccc(-c3ccc(CN4CCOCC4)cc3)n2n1)C1CC1
- Properties:
- ChEMBL ID: CHEMBL3360353
- Molecule type: Small molecule
- Molecular weight: 377.45
- Heavy atoms: 28
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 5
- TPSA: 71.76
- LogP: 2.58
- Rotatable bonds: 5
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.38
- QED: 0.74

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 5.55
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 2843; units nM; pChEMBL 5.55; comment 1034205

## Query Molecule B
- Canonical SMILES: O=C(Nc1nc2cccc(-c3ccc(CN4CCC(F)(F)CC4)cc3)n2n1)C1CC1
- Properties:
- ChEMBL ID: CHEMBL3360356
- Molecule type: Small molecule
- Molecular weight: 411.46
- Heavy atoms: 30
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 4
- TPSA: 62.53
- LogP: 3.98
- Rotatable bonds: 5
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.41
- QED: 0.69

## Molecule Similarity
- Weighted Tanimoto: 0.78

Answer: 6.71