molecular function regulator activity molecular sensor activity https://github.com/geneontology/go-ontology/issues/28772 pg GO:0140299 Reactome:R-HSA-9854368 molecular_function 2018-12-10T14:30:28Z small molecule sensor activity small molecular sensor activity small molecule sensing activity Binding to a molecule and eliciting a change in the protein's activity in response to the intracellular level of that molecule.