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.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Cells, Cultured
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Cerebellum / cytology
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Cerebellum / drug effects*
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Disulfides
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Kinetics
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Molecular Sequence Data
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Molecular Weight
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Neurotoxins / chemistry*
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Neurotoxins / genetics
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Neurotoxins / isolation & purification
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Neurotoxins / pharmacology
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Patch-Clamp Techniques
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Peptides / chemistry*
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Peptides / isolation & purification
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Peptides / metabolism
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Peptides / pharmacology
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Potassium Channels / drug effects*
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Rats
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Rats, Wistar
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Scorpion Venoms / chemistry*
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Scorpion Venoms / genetics
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Scorpion Venoms / isolation & purification
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Scorpion Venoms / pharmacology
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Scorpions / chemistry*
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Sequence Homology, Amino Acid
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Solubility
Substances
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Disulfides
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Neurotoxins
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Peptides
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Potassium Channels
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Scorpion Venoms
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discrepin peptide, rat
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discrepin protein, Tityus discrepans