title: Discrepin, a new peptide of the sub-family alpha-ktx15, isolated from the scorpion Tityus discrepans irreversibly blocks K+ -channels (IA currents) of cerebellum granular cells.
abstract: A new peptide was purified from the venom of the Venezuelan scorpion Tityus discrepans, by high-performance liquid chromatography and its amino acid sequence was completed by Edman degradation and mass spectrometry analysis. It contains 38 amino acid residues with a molecular weight of 4177.7 atomic mass units, tightly folded by three disulfide bridges, and has a pyroglutamic acid at the N-terminal region. This peptide, named Discrepin, was shown to block preferentially the IA currents of the voltage-dependent K+ -channel of rat cerebellum granular cells in culture. The K+ -currents are inhibited in an apparently irreversible manner, whose 50% inhibitory effect is reached with a 190 nM toxin concentration. The systematic nomenclature proposed for this toxin is alpha-KTx15.6.
authors.affiliation: Laboratory of Cellular Neuropharmacology, Biochemistry and Biophysics Center, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020-A, Venezuela.
authors.forename: Gina
authors.initials: G
authors.lastname: D'Suze
authors.forename: Cesar V F
authors.initials: CV
authors.lastname: Batista
authors.forename: Andrea
authors.initials: A
authors.lastname: Frau
authors.forename: Anna Rosa
authors.initials: AR
authors.lastname: Murgia
authors.forename: Fernando Z
authors.initials: FZ
authors.lastname: Zamudio
authors.forename: Carlos
authors.initials: C
authors.lastname: Sevcik
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Prestipino
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects*; D004220:Disulfides; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D012605:Scorpions / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D012995:Solubility
chemical_list: D004220:Disulfides; D009498:Neurotoxins; D010455:Peptides; D015221:Potassium Channels; D012604:Scorpion Venoms; C492486:discrepin peptide, rat; C509989:discrepin protein, Tityus discrepans