## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Biochemical Assay: IDH1-R132H, IDH1-R132C, IDH2-R172K and IDH2-R140Q mutant enzymes catalyze the conversion of αKG to 2HG. 2HG is analyzed using in-line solid phase extraction and mass spectrometry. This analysis is carried out in a RapidFire® instrument coupled to a 6460 triple quadrupole mass spectrometer (G6460A Agilent).IDH1 mutant (R132H and R132C) and IDH2 mutant (R140Q and R172K) proteins containing N-terminal His-tag are expressed in E.coli and purified using nickel affinity chromatography. The enzyme assays are carried out in V-bottom 96 well polypropylene plates containing 100 mM Tris-HCl buffer, 1 mM DTT, 0.01% TRITON X-100, 120 mM NaCl. For IDH1 R132H, α-ketoglutarate, NADPH and MnCl2 are included at final concentrations of 300 μM, 2.5 μM and 300 μM respectively. For IDH1 R132C, α-ketoglutarate, NADPH and MnCl2 are included at final concentrations of 100 μM, 10 μM and 100 μM respectively. For IDH2 R172K, α-ketoglutarate, NADPH and MnCl2 are included at final concentrations of 150 μM, 10 μM and 150 μM respectively. For IDH2 R140Q, α-ketoglutarate, NADPH and MnCl2 are included at final concentrations of 3000 μM, 10 μM and 100 μM respectively. Final pH=7. Test compound dissolved in DMSO stock is diluted in the reaction mix at a final DMSO concentration of 4%. Compounds are tested in dose-response format. The assay is started by addition of enzyme. Enzymes are used at the following final concentrations: IDH1 R132H, 2 nM; IDH1 R132C, 0.5 nM; IDH2 R172K, 1.2 nM; IDH2 R140Q, 1.2 nM. After 90 minutes the reaction is quenched by adding ACN (50:50) containing 3-hydroxy-1,5-pentanedioic-2,2,3,4,4-d5 acid (5d5-3HG) as an internal standard for mass spectrometry analysis and quantitation of reaction product. 2-Hydroxyglutarate (2HG) in quenched samples is separated using strong anionic exchange column chromatography (Phenomenex Strata-X-A SecurityGuard) and analyzed by mass spectrometry in a 6460 triple quadrupole mass spectrometer (G6460A Agilent). The 2HG signal detected is transformed into an analyte concentration using a calibration curve generated using known 2HG concentrations. For each compound tested, the % inhibition is calculated using a DMSO control sample as 0% inhibition and a no enzyme control as 100% inhibition.
- Target name: Isocitrate dehydrogenase [NADP] cytoplasmic
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: C=CC(=O)N1CCN(C(CC2CC2)c2ccc([C@H](C)Nc3ncc4c(n3)N(C)C(=O)OC4)cc2)CC1
- Properties:
- ChEMBL ID: CHEMBL5954158
- Molecular weight: 490.61
- Heavy atoms: 36
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 7
- TPSA: 90.9
- LogP: 3.91
- Rotatable bonds: 8
- Ring count: 5
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.48
- QED: 0.56

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 7.94
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 15.6; units nM; pChEMBL 7.81; comment 1036069
- type IC50; relation =; value 8.69; units nM; pChEMBL 8.06; comment 1036073

## Query Molecule B
- Canonical SMILES: C=CC(=O)N1CCN(C(CC2CC2)c2ccc([C@H](C)Nc3cc4c(cn3)COC(=O)N4C)cc2)CC1
- Properties:
- ChEMBL ID: CHEMBL5802039
- Molecular weight: 489.62
- Heavy atoms: 36
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 6
- TPSA: 78.01
- LogP: 4.51
- Rotatable bonds: 8
- Ring count: 5
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.46
- QED: 0.55

## Molecule Similarity
- Weighted Tanimoto: 0.74

Answer: 7.8