tamoxifen   Click here for help

GtoPdb Ligand ID: 1016

Synonyms: ICI-46474 | Nolvadex® | Soltamox®
Approved drug PDB Ligand
tamoxifen is an approved drug (FDA (1977))
Compound class: Synthetic organic
Comment: Tamoxifen can be classed as a mixed agonist/antagonist of the estrogen -α and -β receptors, as its activity depends on the tissue in which the receptor is expressed. ChEMBL classify this compound as an ERα modulator, while it is described as a selective estrogen receptor modulator by Burris et al. in their 2013 review [1]. Tamoxifen can be considered as a prodrug as its three main metabolites exhibit higher affinity and specificity than tamoxifen at the ERα and ERβ receptors.
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Ligand Activity Visualisation Charts

These are box plot that provide a unique visualisation, summarising all the activity data for a ligand taken from ChEMBL and GtoPdb across multiple targets and species. Click on a plot to see the median, interquartile range, low and high data points. A value of zero indicates that no data are available. A separate chart is created for each target, and where possible the algorithm tries to merge ChEMBL and GtoPdb targets by matching them on name and UniProt accession, for each available species. However, please note that inconsistency in naming of targets may lead to data for the same target being reported across multiple charts.

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View interactive charts of activity data across species

tamoxifen is commercially available from our sponsors

2D Structure
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2D Structure

An image of the ligand's 2D structure. For small molecules with SMILES these are drawn using the NCI/CADD Chemical Identifier Resolver. Click on the image to access the chemical structure search tool with the ligand pre-loaded in the structure editor. For other types of ligands, e.g. longer nucleotides and peptides, a manually drawn representation of the molecule may be provided.

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Physico-chemical Properties
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Physico-chemical Properties

Calculated molecular properties are available for small molecules and natural products (not peptides). Properties were generated using the CDK toolkit. All properties were selected to enable the prediction of the Lipinski Rule-of-Five profile or ‘druglikeness’ for each ligand. For more info on each category see the help pages.

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Hydrogen bond acceptors 1
Hydrogen bond donors 0
Rotatable bonds 8
Topological polar surface area 12.47
Molecular weight 371.22
XLogP 7.14
No. Lipinski's rules broken 1
SMILES / InChI / InChIKey
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SMILES / InChI / InChIKey

SMILES (Simplified Molecular Input Line Entry Specification) A specification for unambiguously describing the structure of chemical molecules using short ASCII strings. Canonical SMILES specify a unique representation of the 2D structure without chiral or isotopic specifications. Isomeric SMILES include chiral specification and isotopes.

Standard InChI (IUPAC International Chemical Identifier) and InChIKey InChI is a non-proprietary, standard, textual identifier for chemical substances designed to facilitate linking of information and database searching. An InChIKey is a simplified version of a full InChI, designed for easier web searching.

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Canonical SMILES CCC(=C(c1ccccc1)c1ccc(cc1)OCCN(C)C)c1ccccc1
Isomeric SMILES CC/C(=C(\c1ccccc1)/c1ccc(cc1)OCCN(C)C)/c1ccccc1
InChI InChI=1S/C26H29NO/c1-4-25(21-11-7-5-8-12-21)26(22-13-9-6-10-14-22)23-15-17-24(18-16-23)28-20-19-27(2)3/h5-18H,4,19-20H2,1-3H3/b26-25-
InChI Key NKANXQFJJICGDU-QPLCGJKRSA-N
Bioactivity Comments
Tamoxifen is one of a number of drugs that are cationic amphiphilic in nature, for which anti-SARS-CoV-2 activity has been identified in drug repurposing screens. Tummino et al. (2021; bioRxiv preprint PMID: 33791693 target="_blank") suggest that this antiviral activity is most likely a result of the drug promoting phospholipidosis via disruption of lipid homeostasis.
Enzymes Catalysing Reactions with this Compound as a Substrate or Product
Enzyme EC number Reaction Reference
CYP3A4 2
Selectivity at GPCRs
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Target Sp. Type Action Value Parameter Concentration range (M) Reference
GPER Hs Agonist Full agonist 6.0 pKi - 4
⤷ pKi 6.0 [4]
Selectivity at ion channels
Key to terms and symbols Click column headers to sort
Target Sp. Type Action Value Parameter Concentration range (M) Reference
Maxi Cl- Hs Activator (extracellular tamoxifen) - - - -
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VRAC Hs Channel blocker - - - -
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Selectivity at nuclear hormone receptors
Key to terms and symbols Click column headers to sort
Target Sp. Type Action Value Parameter Concentration range (M) Reference
Estrogen receptor-α Primary target of this compound Hs Agonist Agonist 7.8 pKi - 3
⤷ pKi 7.8 [3]
Estrogen receptor-α Primary target of this compound Hs Antagonist Antagonist 7.8 pKi - 3
⤷ pKi 7.8 [3]
Estrogen receptor-β Hs Antagonist Antagonist 7.2 pKi - 3
⤷ pKi 7.2 [3]
Estrogen receptor-β Hs Agonist Agonist 7.2 pKi - 3
⤷ pKi 7.2 [3]
Targets where the ligand is described in the comment field
Target Comment
ClC-3 insensitive to the channel blockers DIDS, NPPB and tamoxifen (10 μM)
Maxi Cl- Maxi Cl- is also activated by G protein-coupled receptors and cell swelling. Tamoxifen and toremifene are examples of triphenylethylene anti-oestrogens
Ligand mentioned in the following text fields
G protein-coupled estrogen receptor overview
3A. Estrogen receptors comments
Glycine receptors comments
Maxi chloride channel comments