## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: HTRF PI3K Biochemical Assay: Compounds are serially diluted (3-fold in 100% DMSO) across a 384-well polypropylene source plated from column 3 to column 12 and column 13 to column 22, to yield 10 concentration dose response for each test compound. Columns 1, 2, 23 and 24 contain either only DMSO or pharmacological known control inhibitor. Once titrations are made, 2.5 nL of the compounds on 384 well plates are reformatted and transferred by acoustic dispense in quadruplicates to a 1536 assay plate (Greiner) to assay across all four PI3K isoform enzymes.The PI3-Kinase biochemical assay was optimized using the HTRF kit provided by Upstate (Millipore). The assay kit contains six reagents: 1) 4× Reaction Buffer; 2) native PIP2 (substrate); 3) Stop (EDTA); 4) Detection Mix A (Streptavidin-APC); 5) Detection Mix B (Eu-labeled Anti-GST plus GST-tagged PH-domain); 6) Detection Mix C. In addition, the following items were obtained or purchased; PI3Kinase (alpha 14-602, beta 14-603, gamma 14-558 and delta 14-604 from Upstate; Millipore), dithiothreitol (Sigma, D-5545), Adenosine-5′ triphosphate (InVitrogen, Cat#AS001A), native PIP3 (PI(3,4,5)P3, diC8, H+, CELLSIGNALS, INC. Cat #907) DMSO (Sigma, 472301).PI3Kinase Reaction Buffer is prepared by dilution the stock 1:4 with de-ionized water. DTT, PIP2 and Biotin-PIP3 were added to 1536 assay plate at a final concentration of 5 mM, 5 mM and 25 nM on the day of use. Enzyme addition and compound pre-incubation are initiated by the addition of 1.25 ul of PI3K (at twice its final concentration) in the 1× reaction buffer to all wells using a BioRaptor. Plates are incubated at RT for 15 minutes. Reactions are initiated by addition of 1.25 ul of 2× substrate solution (PIP2 and ATP in 1× reaction buffer) using BioRaptor. Plates are incubated in humidified chamber at RT for one hour. Reactions are quenched by addition of 0.62 uL of stop solution to all wells using the BioRaptor. The quenched reactions are then processed to detect product formation by adding 0.62 uL of Detection Solution to all wells using the BioRaptor (Detection mix C, Detection Mix A, and Detection Mix B combined together in an 18:1:1 ratio prepared 2 hours prior to use). Following a one hour incubation in the dark, the HTRF signal is measured on the Envision plate reader set for 330 nm excitation and dual emission detection at 620 nM (Eu) and 665 nM (APC).
- Assay organism: Homo sapiens
- Target name: Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: CC[C@H](Nc1ncnc2c1nc(-c1cnc(C)nc1)n2CC)C(=O)N1CCS(=O)(=O)CC1
- Properties:
- ChEMBL ID: CHEMBL5761148
- Molecular weight: 458.55
- Heavy atoms: 32
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 9
- TPSA: 135.86
- LogP: 1.06
- Rotatable bonds: 6
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.5
- QED: 0.57

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 7.51
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 31; units nM; pChEMBL 7.51; comment 715274

## Query Molecule B
- Canonical SMILES: CC[C@H](Nc1ncnc2c1nc(-c1cnc(C)nc1)n2CC)C(=O)N1CCOC(C)(C)C1
- Properties:
- ChEMBL ID: CHEMBL5794932
- Molecular weight: 438.54
- Heavy atoms: 32
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 8
- TPSA: 110.95
- LogP: 2.44
- Rotatable bonds: 6
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.55
- QED: 0.62

## Molecule Similarity
- Weighted Tanimoto: 0.72

Answer: 8.01