## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: In Vitro PI3K Alpha Binding Assay: N-terminally His-tagged PI3K alpha (Cat. No. PV4789; 0.49 mg/ml), Alexa Fluor® 647 labeled kinase Tracer 314 (Cat. No. PV6087), Biotin anti-His Tag antibody (Cat. No PV6089) and LanthaScreen® Eu-Streptavidin (Cat. No. PV5899) were purchased from Life Technologies. The 1× Kinase Buffer A consists of 50 mM HEPES pH 7.5, 10 mM MgCl2, 1 mM EGTA, and 0.01% (v/v) Brij-35 (Sigma Cat. No. B4184-100ML).A 4-fold serial dilution of each compound to be tested was prepared in DMSO (master dilution) in a 96-well polystyrene plate (Falcon Cat. No. 353072, flat bottom) with the highest concentration at 1000 μM and the lowest at 0 μM. The master dilution series were diluted further 33.3-fold into Kinase Buffer A by transferring 5 μl of each concentration of diluted compound to 162 μl Kinase Buffer A in a new 96-well plate resulting to a 3-fold serially compound dilution. Based on a Tracer 314 titration experiment a working concentration of 20 nM was chosen. Therefore a 60 nM Tracer 314 solution in Kinase Buffer A was prepared resulting in a 3-fold concentrated solution. A 3-fold concentrated kinase/antibody solution at 15 nM kinase, 6 nM antibody and 6 nM Eu-Streptavidin was prepared in Kinase Buffer A. Five μl of each 3× serially diluted compound were dispensed in a 384-well plate in duplicate. Then to each well 5 μl of 3× kinase/antibody mixture was added followed by the addition of 5 μl 3× Tracer 314 solution. After 1 h incubation at rt, time-resolved FRET was measured with a Synergy 4 multi-mode microplate reader (Biotek Instruments) using the following settings: 100 μs delay before data collection, 200 μs time for data collection, 10 measurements per data point. Emission filter: 665 nm/8 nm with sensitivity set to 163 and 620 nm/10 nm with sensitivity set to 135; Excitation filter: 340 nm/30 nm; Dichroic mirror 400 nm.
- Assay organism: Homo sapiens
- Target name: Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: Nc1cc(C(F)(F)F)c(-c2nc(N3CCOCC3)c3c(n2)N2CCOC[C@H]2C3)cn1
- Properties:
- ChEMBL ID: CHEMBL4536322
- Molecule type: Unknown
- Molecular weight: 422.41
- Heavy atoms: 30
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 8
- TPSA: 89.63
- LogP: 1.74
- Rotatable bonds: 2
- Ring count: 5
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.53
- QED: 0.78

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 6.41
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 390.4; units nM; pChEMBL 6.41; comment 486942

## Query Molecule B
- Canonical SMILES: Nc1ncc(-c2nc(N3CCOCC3)c3c(n2)N2CCOC[C@@H]2C3)cn1
- Properties:
- ChEMBL ID: CHEMBL5218581
- Molecular weight: 355.4
- Heavy atoms: 26
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 9
- TPSA: 102.52
- LogP: 0.11
- Rotatable bonds: 2
- Ring count: 5
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.53
- QED: 0.8

## Molecule Similarity
- Weighted Tanimoto: 0.66

Answer: 7.12