## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: Ki
- Label type: continuous
- Binary semantics: pchembl
- Assay description: CDK2/Cyclin E1 Mobility Shift Assay : The purpose of the CDK2/Cyclin E1 assay is to evaluate the inhibition (% inhibition, Kiapp and Ki values) of small molecule inhibitors by using a fluorescence-based microfluidic mobility shift assay. CDK2/Cyclin E1 catalyzes the production of ADP from ATP that accompanies the phosphoryl transfer to the substrate peptide FL-Peptide-18 (5-FAM-QSPKKG-CONH2) (SEQ ID NO:1). (CPC Scientific, Sunnyvale, Calif.). The mobility shift assay electrophoretically separates the fluorescently labeled peptides (substrate and phosphorylated product) following the kinase reaction. Both substrate and product are measured and the ratio of these values is used to generate % conversion of substrate to product by the LabChip EZ Reader. Wild-type full length CDK2/wild-type full length Cyclin E1 enzyme complex was produced in-house (baculoviral expression, LJIC-2080/LJIC-2103) and phosphorylated by CDK7/Cyclin H1/Mat1 enzyme complex with CDK2:CDK7 ratio of 50:1 (concentration mg/mL) in the presence of 10 mM MgCl2 and 5 mM ATP at room temperature for one hour. Typical reaction solutions (50 μL final reaction volume) contained 2% DMSO (±inhibitor), 4 mM MgCl2, 1 mM DTT, 150 μM ATP (ATP Km=67.4 μM), 0.01% Tween-20, 3 μM FL-Peptide-18, and 0.36 nM (catalytically competent active site) phosphorylated wild-type full length CDK2/Cyclin E1 enzyme complex in 25 mM HEPES buffer at pH 7.15. The assay was initiated with the addition of ATP, following a fifteen minutes pre-incubation of enzyme and inhibitor at room temperature in the reaction mixture. The reaction was stopped after 45 minutes at room temperature by the addition of 50 μL of 80 mM EDTA, pH 7.5. The Ki value was determined from the fit of the data to the Morrison tight-binding competitive inhibition equation with the enzyme concentration as a variable.
- Assay organism: Homo sapiens
- Target name: Cyclin-dependent kinase 2/cyclin E1
- Target type: PROTEIN COMPLEX
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: CC(C)S(=O)(=O)N1CCC(Nc2ncc3cc(CCO)c(=O)n(C4CCCC4)c3n2)CC1
- Properties:
- ChEMBL ID: CHEMBL5754441
- Molecular weight: 463.6
- Heavy atoms: 32
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 7
- TPSA: 117.42
- LogP: 2.06
- Rotatable bonds: 7
- Ring count: 4
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.68
- QED: 0.65

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 8.5
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type Ki; relation =; value 3.14; units nM; pChEMBL 8.5; comment 965577

## Query Molecule B
- Canonical SMILES: Cc1cc2cnc(NC3CCN(S(C)(=O)=O)CC3)nc2n([C@@H]2CCC[C@@H](O)C2)c1=O
- Properties:
- ChEMBL ID: CHEMBL5816019
- Molecular weight: 435.55
- Heavy atoms: 30
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 7
- TPSA: 117.42
- LogP: 1.41
- Rotatable bonds: 4
- Ring count: 4
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.65
- QED: 0.75

## Molecule Similarity
- Weighted Tanimoto: 0.58

Answer: 9.08