The KND olygopeptide as a putative endogenous prototype of Delta Sleep Inducing Peptide (DSIP). comparative study of biological properties

Biological properties of the known Delta Sleep-Inducing Peptide (DSIP, WAGGDASGE) were studied in vivo in comparison with those of a new DSIP-homologous peptide (WKGGNASGE — ([K ², N ⁵]DSIP, KND). This new peptide was recently discovered as the 324–332 fragment of the human lysine-specific histone demethylase 3B (EC 1.14.11, Swiss-Prot: Q7LBC6.1, 1761 a.a.) in the course of a computer search in available databases of proteins and nucleic acids. This demethylase belongs to the JmjC-domain-containing family of histone demethylases which are encoded by the JMJD1B gene and present in tissues of various mammals. These studies confirmed our preliminary conclusions on the functional similarity between the biological activities of DSIP and KND. The examined antioxidative, anticonvulsive, and behavioral effects of KND proved to be more pronounced than those of DSIP. The obtained results additionally sup-ported our hypothesis about KND being an endogenous prototype of a “real” DSIP.