## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Solid Phase Receptor Assay (SPRA) for alpha8beta1 Function: Recombinant mouse nephronectin protein (R&D Systems, Inc, 4298-NP) diluted to 1 μg/mL in TBS+ buffer (25 mM Tris pH 7.4, 137 mM NaCl, 2.7 mM KCl, 1 mM CaCl2, 1 mM MgCl2, 1 mM MnCl2) was added to wells (50 al/well) of a 96-well half-well transparent microtiter plate (Greiner 675061), and incubated overnight at 4° C. Wells were washed 3 times with 150 μL TBS+ and 150 μL of blocking buffer (TBS+ with 1% bovine serum albumin, Sigma A7906) were added. The plate was incubated for 1 hr at 37° C. and then washed 3× with TBS+. Recombinant human integrin α8β1 (R&D Systems, pre-launch) was diluted to 0.25 μg/mL in TBS+/0.1% bovine serum albumin. Compounds were diluted 1:100 into the integrin solution and 50 μL added to empty wells of the washed nephronectin-coated plate according to a standard template with each sample repeated in triplicate. After incubation for two hours at room temperature, the plate was washed 3× with 150 μL of TBS+. To each well, 50 μL of biotinylated anti-β1 antibody (R&D Systems, BAF1778) at 0.5 μg/mL in TBS+/0.1% BSA were added and the plate was covered and incubated for 1 hr at room temperature. After washing the plate 3× with 150 μL of TBS+ buffer, 50 μL of streptavidin-conjugated horseradish peroxidase (R&D Systems, DY998) diluted in TBS+ blocking buffer were added to the wells and the plate incubated for 20 min at room temperature. The plate was washed 3× with TBS+ followed by 50 μL of TMB substrate (Sigma T4444) added to each well and the plate incubated for 20 min at room temperature. Plates were read by colorimetric detection at 650 nm wavelength using a Tecan Safire II plate reader. Concentration-response curves were constructed by non-linear regression (best fit) analysis, and IC50 values were calculated for each compound.
- Assay organism: Homo sapiens
- Target name: Integrin alpha-5/alpha-8
- Target type: PROTEIN COMPLEX
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: O=C(O)C[C@H](NC(=O)CNC(=O)c1cc(O)cc(NC2=NCC(O)CN2)c1)c1cc(Cl)cc(Br)c1
- Properties:
- ChEMBL ID: CHEMBL5802710
- Molecular weight: 568.81
- Heavy atoms: 35
- Hydrogen bond donors: 7
- Hydrogen bond acceptors: 8
- TPSA: 172.38
- LogP: 1.6
- Rotatable bonds: 8
- Ring count: 3
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.27
- QED: 0.25

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 9.3
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 0.5; units nM; pChEMBL 9.3; comment 876457

## Query Molecule B
- Canonical SMILES: O=C(O)C[C@H](NC(=O)CNC(=O)c1cncc(NC2=NCC(O)CN2)c1)c1cc(Cl)cc(Br)c1
- Properties:
- ChEMBL ID: CHEMBL5889173
- Molecular weight: 553.8
- Heavy atoms: 34
- Hydrogen bond donors: 6
- Hydrogen bond acceptors: 8
- TPSA: 165.04
- LogP: 1.29
- Rotatable bonds: 8
- Ring count: 3
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.29
- QED: 0.28

## Molecule Similarity
- Weighted Tanimoto: 0.8

Answer: 9.22