## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: Ki
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Biochemical JAK Assay: A panel of four LanthaScreen JAK biochemical assays (JAK1, 2, 3 and Tyk2) were carried in a common kinase reaction buffer (50 mM HEPES, pH 7.5, 0.01% Brij-35, 10 mM MgCl2, and 1 mM EGTA). Recombinant GST-tagged JAK enzymes and a GFP-tagged STAT1 peptide substrate were obtained from Life Technologies.Serially diluted compounds were pre-incubated with each of the four JAK enzymes and the substrate in white 384-well microplates (Corning) at ambient temperature for lh. ATP was subsequently added to initiate the kinase reactions in 10 μL total volume, with 1% DMSO. The final enzyme concentrations for JAK1, 2, 3 and Tyk2 are 4.2 nM, 0.1 nM, 1 nM, and 0.25 nM respectively; the corresponding Km ATP concentrations used are 25 μM, 3 μM, 1.6 μM, and 10 μM; while the substrate concentration is 200 nM for all four assays. Kinase reactions were allowed to proceed for 1 hour at ambient temperature before a 10 μL preparation of EDTA (10 mM final concentration) and Tb-anti-pSTAT1 (pTyr701) antibody (Life Technologies, 2 nM final concentration) in TR-FRET dilution buffer (Life Technologies) was added. The plates were allowed to incubate at ambient temperature for lh before being read on the EnVision reader (Perkin Elmer). Emission ratio signals (520 nm/495 nm) were recorded and utilized to calculate the percent inhibition values based on DMSO and background controls.For dose-response analysis, percent inhibition data were plotted vs. compound concentrations, and IC50 values were determined from a 4-parameter robust fit model with the Prism software (GraphPad Software). Results were expressed as pIC50 (negative logarithm of IC50) and subsequently converted to pKi (negative logarithm of dissociation constant, Ki) using the Cheng-Prusoff equation.Test compounds having a higher pKi value in each of the four JAK assays show greater inhibition of JAK activity. Compounds of the invention tested in this assay typically exhibited pKi values between about 7 and about 10.3
- Assay organism: Homo sapiens
- Target name: Tyrosine-protein kinase JAK2
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: Cc1cc(Nc2cc3ncccc3c(N[C@@H]3C[C@H]4CC[C@@H](C3)N4S(C)(=O)=O)n2)n[nH]1
- Properties:
- ChEMBL ID: CHEMBL5873330
- Molecular weight: 427.53
- Heavy atoms: 30
- Hydrogen bond donors: 3
- Hydrogen bond acceptors: 7
- TPSA: 115.9
- LogP: 2.77
- Rotatable bonds: 5
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.45
- QED: 0.57

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 9.26
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type Ki; relation =; value 0.55; units nM; pChEMBL 9.26; comment 526819

## Query Molecule B
- Canonical SMILES: COc1cnc2cc(Nc3cc(C)[nH]n3)nc(N[C@@H]3C[C@H]4CCC[C@@H](C3)N4CCCF)c2c1
- Properties:
- ChEMBL ID: CHEMBL6012138
- Molecular weight: 453.57
- Heavy atoms: 33
- Hydrogen bond donors: 3
- Hydrogen bond acceptors: 7
- TPSA: 90.99
- LogP: 4.57
- Rotatable bonds: 8
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.54
- QED: 0.46

## Molecule Similarity
- Weighted Tanimoto: 0.49

Answer: 7.3