## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: LRRK2 Assay: LRRK2 kinase activity was measured using Lantha Screen technology from Invitrogen. GST-tagged truncated LRRK2 from Invitrogen (Cat #PV4874) was incubated with a fluorescein-labeled peptide substrate based upon ezrin/radixin/moesin (ERM), also known as LRRKtide (Invitrogen cat #PR8976A), in the presence of a dose response of compound. Upon completion, the assay was stopped and detected with a terbium labeled anti-phospho-ERM antibody (Invitrogen, cat #PR8975A). The assay was carried out under the following protocol: The compound dose response was prepared by diluting compound to a top concentration of 0.3 mM in 100% DMSO and serial diluted by half-log in DMSO to give an 11 point curve, 100× final assay concentration. Using Echo acoustic dispensing, 60 nL of compound was transferred to a low volume Corning 384-well assay plate. 3 μL of a working solution of substrate (200 nM LRRKtide, 2 mM ATP) prepared in assay buffer (50 mM HEPES, pH 7.5, 3 mM MgCl2, with 2 mM DTT and 0.01% Brij35 added fresh) was added to the 60 nL compound assay plate. The kinase reaction was started with 3 μL of a working solution of LRRK2 enzyme at a concentration of 4 μg/mL. The final reaction concentrations were 100 nM LRRKtide, 1 mM ATP, 2 μg/mL LRRK2 enzyme and a compound dose response with a top dose of 3 μM. The reaction was allowed to progress at room temperature for 30 minutes and then stopped with the addition of 6 μL of detection buffer (20 mM Tris pH 7.6, 0.01% NP-40, 6 mM EDTA with 2 nM terbium labeled anti-phospho-ERM). After an incubation of 1 hour at room temperature, the plate was read on an Envision with an excitation wavelength of 340 nm and a reading emission at both 520 nm and 495 nm. The ratio of the 520 nm and 495 nm emission was used to analyze the data. Inhibition of mutant G2019S LRRK2 (Invitrogen cat #PV4881) was measured in the exact same method. All final concentrations of substrate ATP and enzyme were the same.
- Assay organism: Homo sapiens
- Target name: Leucine-rich repeat serine/threonine-protein kinase 2
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: C[C@@H]1C[C@H](n2c([C@H]3CCOC3)nc3cnc4ccc(C(F)F)cc4c32)CCO1
- Properties:
- ChEMBL ID: CHEMBL5854501
- Molecular weight: 387.43
- Heavy atoms: 28
- Hydrogen bond donors: 0
- Hydrogen bond acceptors: 4
- TPSA: 49.17
- LogP: 4.77
- Rotatable bonds: 3
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.52
- QED: 0.65

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 7.78
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 16.6; units nM; pChEMBL 7.78; comment 1103780

## Query Molecule B
- Canonical SMILES: C[C@@H]1C[C@H](n2c([C@H]3CC[C@@H](F)C3)nc3cnc4ccc(C#N)cc4c32)CCO1
- Properties:
- ChEMBL ID: CHEMBL5799800
- Molecular weight: 378.45
- Heavy atoms: 28
- Hydrogen bond donors: 0
- Hydrogen bond acceptors: 4
- TPSA: 63.73
- LogP: 4.8
- Rotatable bonds: 2
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.5
- QED: 0.64

## Molecule Similarity
- Weighted Tanimoto: 0.6

Answer: 8.2