## Endpoint to Predict
- Endpoint scope: assay
- Measurement type: IC50
- Label type: continuous
- Binary semantics: pchembl
- Assay description: IMAP TR-FRET PDE2A assay: An IMAP TR-FRET-based phosphodiesterase assay was developed using the PDE2A isoform. IMAP technology is based on high-affinity binding of phosphate by immobilized metal (MIII) coordination complexes on nanoparticles. The IMAP binding reagent recognizes phosphate groups on AMP or GMP generated from cAMP or cGMP in a PDE reaction. Cyclic nucleotides that carry a phosphodiester bond and not a free phosphate are not recognized by the binding reagent. The time resolved fluorescence resonance energy transfer (TR-FRET) is afforded by a Terbium (Tb)-Donor pre-bound to the nanoparticles. FRET occurs when the fluorescent-labeled AMP or GMP product of a PDE reaction binds and comes into close proximity to the Tb-Donor complex. Due to the long lifetime of Tb fluorescence, detection can be run in time-resolved mode to reduce or eliminate interference from auto-fluorescent compounds.The IMAP TR-FRET PDE2A assay was performed in 1536-well white plates. A total of 250 pg per well of FLAG-tagged PDE2A 1 (amino acids 2-941) was dispensed in 2.5 μL IMAP assay buffer consisting of 10 mM Tris pH 7.2, 10 mM MgCl2, 1 mM DTT, and 0.1% fatty acid free BSA. 30 nL of compound was then added from 1 mM stocks in DMSO using a Kalypsys Pintool. Plates were incubated for 5 min at room temperature before dispensing 1.5 μL of 533 nM FAM-cAMP substrate for a final concentration of 200 nM. Following a brief centrifugation, plates were incubated for 30 min at room temperature. The assay was terminated by adding 5 μL IMAP binding reagent Tb complex to each well which was prepared according to manufacturer's recommendations (Molecular Devices). Plates were incubated an additional 120 minutes at room temperature and read on a Viewlux plate reader. All compounds were solvated at a concentration of 10 mM in DMSO and tested in 11-point half-log dose-response. Curve fitting and IC50 values were determined using a standard four parameter fit.
- Target name: cGMP-dependent 3',5'-cyclic phosphodiesterase
- Target type: SINGLE PROTEIN
- Target organism: Homo sapiens

## Reference Molecule A
- Canonical SMILES: Cc1nc2c(c(C3CC3)nn2[C@H](C)c2ccc(C(F)(F)F)cn2)c(=O)[nH]1
- Properties:
- ChEMBL ID: CHEMBL5961776
- Molecular weight: 363.34
- Heavy atoms: 26
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 4
- TPSA: 76.46
- LogP: 3.33
- Rotatable bonds: 3
- Ring count: 4
- Aromatic rings: 3
- Formal charge: 0
- Fraction Csp3: 0.41
- QED: 0.77

## Known Reference Result on This Endpoint
- Molecule A clean result: median pChEMBL = 5.26
- This result is provided as context for predicting Molecule B on the same endpoint.

## Reference Molecule A Other ChEMBL Evidence
- type IC50; relation =; value 5500; units nM; pChEMBL 5.26; comment 1026921

## Query Molecule B
- Canonical SMILES: COc1ccc(Cc2nc3c(c(C4CC4)nn3[C@H](C)c3ccc(C(F)(F)F)nc3)c(=O)[nH]2)nc1
- Properties:
- ChEMBL ID: CHEMBL6000786
- Molecular weight: 470.46
- Heavy atoms: 34
- Hydrogen bond donors: 1
- Hydrogen bond acceptors: 6
- TPSA: 98.58
- LogP: 4.01
- Rotatable bonds: 6
- Ring count: 5
- Aromatic rings: 4
- Formal charge: 0
- Fraction Csp3: 0.35
- QED: 0.46

## Molecule Similarity
- Weighted Tanimoto: 0.5

Answer: 6.26