## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: Inhibition Activity Assay: IDO1: For testing, 24 μL of enzyme (IDO1) was diluted 100 times with 50 mM KPB to 2400 μL. The concentration of the enzyme solution was 2.6 ng/μL. A 96 well reaction plate (AXYGEN, PCR-96-FLT-C) (hereinafter referred to as the reaction plate) was added with the enzyme solution at 24 μL/well. The blank well was added with 24 μL of KPB [Preparation of KPB buffer (50 mM): 6.8 g of KH2PO4 was weighed using an analytical balance, and placed into a 1000 mL beaker, deionized water was added with a measuring cylinder to 900 ml, the pH was adjusted to 6.5 by 1M KOH, then the mixture was introduced into a 1 L measuring cylinder, and water was added to 1 L. It was stored at 4° C.]. Then, 1 μL of a compound or DMSO was added into the corresponding wells in the reaction plate. Preparation of solution A: 200 μL of 500 mM L-sodium ascorbate were added with 1050 μL of KPB, then the mixture was mixed uniformly for 3 seconds at the maximum speed in a turbine mixer. Solution B: 100 μL of 10 mM tryptophan were added with 100 μL of 100,000 unit/mL catalase, 5 μL of 10 mM methylene blue, and 1050 μL of KPB successively, then the mixture was mixed uniformly for 3 seconds at the maximum speed in a turbine mixer. Then, 1200 μL of solution A and 1200 μL of solution B were taken and mixed uniformly for 3 seconds at the maximum speed in a turbine mixer. The mixture was added to the reaction plate at 24 μL/well. The reaction plate was placed in a plate centrifuge and centrifuged for 15 seconds at the maximum speed, so that the reaction liquids converged to the bottom. The reaction mixture was mixed uniformly for 30 seconds on a shaker, and incubated for 1 hour at 37° C. in a constant temperature incubator. In the reaction plate, 30% (W/V) trichloroacetic acid was added at 10 μL/well, then the mixture was incubated for 15 minutes at 65° C. in an incubator. The reaction plate was centrifuged in a centrifuge for 5 minutes at 4700 RPM at room temperature. Then, 40 μL of the supernatant was transferred from the reaction plate to the corresponding 96 well test plate (Corning, #3599) by a multi-channel pipette. Then, 2% (W/V) 4-(dimethylamino)benzaldehyde/glacial acetic acid solution was added at 40 μL/well, and the mixture was mixed uniformly for 1 minute on a shaker at the maximum speed. After incubation for 2 minutes at room temperature, the absorbance at 480 nm was read on a Synergy HT (BIOTEK) reader.
- Assay organism: Homo sapiens
- Target name: Indoleamine 2,3-dioxygenase 1
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: N#Cc1ccc(N2CCC(C3c4c(F)cccc4-c4cncn43)CC2)cc1F
- Properties:
- ChEMBL ID: CHEMBL5895301
- Molecular weight: 376.41
- Heavy atoms: 28
- Hydrogen bond donors: 0
- Hydrogen bond acceptors: 3
- TPSA: 44.85
- LogP: 4.52
- Rotatable bonds: 2
- Ring count: 5
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.27
- QED: 0.66

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 8.05
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 8.84; units nM; pChEMBL 8.05; comment 996913

## Query Molecule B
- Canonical SMILES: Cn1cc(-c2ccc(N3CCC([C@H]4c5c(F)cccc5-c5cncn54)CC3)cc2)cn1
- Properties:
- ChEMBL ID: CHEMBL4522927
- Molecule type: Unknown
- Molecular weight: 413.5
- Heavy atoms: 31
- Hydrogen bond donors: 0
- Hydrogen bond acceptors: 3
- TPSA: 38.88
- LogP: 4.91
- Rotatable bonds: 3
- Ring count: 6
- Aromatic rings: 4
- Formal charge: 0
- Fraction Csp3: 0.28
- QED: 0.48

## Molecule Similarity
- Weighted Tanimoto: 0.64

Answer: 8.29