## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: EGLN-1 Activity Assay: The EGLN-1 (or EGLN-3) enzyme activity is determined using mass spectrometry (matrix-assisted laser desorption ionization, time-of-flight MS, MALDI-TOF MS-for assay details, see reference (Greis et. al., 2006). Recombinant human EGLN-1-179/426 is prepared as described above and in the Supplemental Data. Full-length recombinant human EGLN-3 is prepared in a similar way, however it is necessary to use the His-MBP-TVMVEGLN-3 fusion for the assay due to the instability of the cleaved protein. For both enzymes, the HIF-1α peptide corresponding to residues 556-574 (DLDLEALAPYIPADDDFQL) (SEQ ID NO. 1) is used as substrate. The reaction is conducted in a total volume of 50 uL containing TrisCl (5 mM, pH 7.5), ascorbate (120 μM), 2-oxoglutarate (3.2 μM), HIF-1α (8.6 μM), and bovine serum albumin (0.01%). The enzyme, quantity predetermined to hydroxylate 20% of substrate in 20 minutes, is added to start the reaction. Where inhibitors are used, compounds are prepared in dimethyl sulfoxide at 10-fold final assay concentration. After 20 minutes at room temperature, the reaction is stopped by transferring 10 μL of reaction mixture to 50 μL of a mass spectrometry matrix solution (α-cyano-4-hydroxycinnamic acid, 5 mg/mL in 50% acetonitrile/0.1% TFA, 5 mM NH4PO4). Two microliters of the mixture is spotted onto a MALDI-TOF MS target plate for analysis with an Applied Biosystems (Foster City, Calif.) 4700 Proteomics Analyzer MALDI-TOF MS equipped with a Nd:YAG laser (355 nm, 3 ns pulse width, 200 Hz repetition rate), Hydroxylated peptide product is identified from substrate by the gain of 16 Da. Data defined as percent conversion of substrate to product is analyzed in GraphPad Prism 4 to calculate IC50 values.
- Assay organism: Homo sapiens
- Target name: Prolyl hydroxylase EGLN3
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: COC(=O)CNC(=O)c1ncc(-c2cccc(Cl)c2)cc1O
- Properties:
- ChEMBL ID: CHEMBL3646212
- Molecule type: Small molecule
- Molecular weight: 320.73
- Heavy atoms: 22
- Hydrogen bond donors: 2
- Hydrogen bond acceptors: 5
- TPSA: 88.52
- LogP: 2.01
- Rotatable bonds: 4
- Ring count: 2
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.13
- QED: 0.84

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 4.67
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 21400; units nM; pChEMBL 4.67; comment 1199721

## Query Molecule B
- Canonical SMILES: O=C(O)CNC(=O)c1ncc(-c2cccc(Cl)c2)cc1O
- Properties:
- ChEMBL ID: CHEMBL3646221
- Preferred name: VADADUSTAT
- Molecule type: Small molecule
- Max clinical phase: 4
- Molecular weight: 306.71
- Heavy atoms: 21
- Hydrogen bond donors: 3
- Hydrogen bond acceptors: 4
- TPSA: 99.52
- LogP: 1.92
- Rotatable bonds: 4
- Ring count: 2
- Aromatic rings: 2
- Formal charge: 0
- Fraction Csp3: 0.07
- QED: 0.8

## Molecule Similarity
- Weighted Tanimoto: 0.75

Answer: 6.41