## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: PI3K-Alpha kinase (PIK3CA) activity, wild-type and H1047R mutant and determining IC50 values for inhibitors: Recombinant, catalytically active human full length PIK3KA Wild-type and H1047R mutant were purchased as 1:1 complex of N-terminal 6×his tagged p110<(catalytic) and untagged p85<(regulatory subunit) from EMD Millipore Sigma (cat. no. 14-602M and 14-792M, respectively). The enzyme stocks were diluted to 5× stocks in buffer (20 mM HEPES pH 7.4, 100 mM NaCl, 0.5 mM EGTA, 0.01% triton-x-100) just before use. PIP2diC8 (Avanti Polar Lipids Inc., cat. no. 850185) or phosphoinositol-4,5-bisphosphate with phosphoserine (PIP2:PS) membrane (Thermo Fisher Scientific, cat. no. PV5100) was used as lipid substrates. PIP2diC8 lyophilized powder and PIP2:PS (1:19) membrane stock (1 mM in PIP2) were separately dissolved in milliQ water to a concentration of 250 uM and stored in −20° C. 10 mM stocks of compounds were serially diluted (3×) in neat DMSO and stored in a dessicator at room temperature. 5× compound stocks in 25% DMSO were prepared fresh from neat DMSO stocks. Wild-type (WT) and H1047R mutant protein, along with buffer components (except ATP), were incubated with or without compound at 27° C. for 1h. After incubation, the reaction was initiated by the addition of 5 uL of 125 uM ATP. A typical assay mixture (25 uL) comprised 40 mM HEPES buffer, pH 7.4, 25 mM MgCl2, 0.01% v/v triton-X-100, 5% v/v DMSO, 20 mM NaCl, 1-5 nM wt or H1047R, 25 uM ATP, and 50 uM PTP2diC8 or PTP2 in membrane. The reaction was allowed to proceed until about 1000 conversion (2.5 uM ADP) after which time, 10 uL of reaction mixture was quenched with 25 uL of transcreener reagent (Transcreener ADP2 FI assay kit, BellBrook labs, Cat. No. 3013). The contents were incubated at rt for 1h and fluorescence was measured using a plate reader (Paradigm, Molecular Devices). The same assay was also run at pH 6 or 6.4 using MOPS buffer (Fisher BioReagents, CAS 1132-61-2). A calibration curve was generated under identical buffer conditions with varying ADP amounts. Using that, the observed fluorescence was converted to uM ADP.
- 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: COC12CC(C1)N(c1cc(=O)c3cc(C)cc(C(C)Nc4ccccc4C(=O)O)c3o1)C2
- Properties:
- ChEMBL ID: CHEMBL5968524
- Molecular weight: 434.49
- Heavy atoms: 32
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 6
- TPSA: 92.01
- LogP: 4.34
- Rotatable bonds: 6
- Ring count: 6
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.36
- QED: 0.6

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 6.12
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 750; units nM; pChEMBL 6.12; comment 1278311

## Query Molecule B
- Canonical SMILES: Cc1cc(C(C)Nc2ccccc2C(=O)O)c2oc(N3CCC4(CCCCO4)CC3)cc(=O)c2c1
- Properties:
- ChEMBL ID: CHEMBL5908771
- Molecular weight: 476.57
- Heavy atoms: 35
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 6
- TPSA: 92.01
- LogP: 5.51
- Rotatable bonds: 5
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.43
- QED: 0.5

## Molecule Similarity
- Weighted Tanimoto: 0.63

Answer: 6.12