HypnoS is a genetically encoded fluorescent sensor for adenosine. It consists of the adenosine deaminase gene from Plasmodium vivax (UniProtKB:A5KE01), into which a circularly permuted enhanced green fluorescent protein (cpEGFP) flanked by linkers has been inserted in between residues 175 and 176. A number of additional mutations have also been introduced during optimization of the sensor and an RSET peptide is present at the N-terminal end of the coding sequence (PMID:40335490).