Anionic currents of chick sensory neurons are affected by a phospholipase A2 purified from the venom of the taipan snake.

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  • Additional Information
    • Source:
      Publisher: Elsevier Pub. Co Country of Publication: Netherlands NLM ID: 0217513 Publication Model: Print Cited Medium: Print ISSN: 0006-3002 (Print) Linking ISSN: 00063002 NLM ISO Abbreviation: Biochim Biophys Acta Subsets: MEDLINE
    • Publication Information:
      Original Publication: Amsterdam : Elsevier Pub. Co.
    • Subject Terms:
      Elapid Venoms/*pharmacology ; Ion Channels/*metabolism ; Neurons, Afferent/*physiology ; Phospholipases A/*pharmacology; Amino Acid Sequence ; Animals ; Anions/metabolism ; Cells, Cultured ; Chick Embryo ; Chloride Channels ; Elapid Venoms/chemistry ; Elapid Venoms/isolation & purification ; Electric Conductivity ; Ganglia, Spinal/cytology ; Ganglia, Spinal/physiology ; Membrane Proteins/metabolism ; Molecular Sequence Data ; Phospholipases A/chemistry ; Phospholipases A/isolation & purification ; Phospholipases A2 ; Reptilian Proteins
    • Abstract:
      A neurotoxic phospholipase A2 was purified from the venom of the taipan snake Oxyuranus scutellatus scutellatus by three consecutive chromatographic steps on ion exchange resins, followed by an affinity column prepared with a phosphatidylcholine derivative attached to Sepharose. The phospholipase was shown to be of type A2 (specific activity of 85 units/mg protein), and an apparent molecular weight of 16,000. Amino acid analysis shows the presence of approx. 150 residues with the N-terminal amino acid sequence: NLAQFGFMIRCANGGSRSALDYADYGC, different from all the phospholipases described until now. This enzyme is lethal to experimental mice (LD50 = 10 micrograms/20 g mouse weight) and affects ionic currents in chick (Gallus domesticus) dorsal root ganglion cells, measured by the whole-cell clamp technique. In symmetrical external/internal ionic solutions, after suppression of Na+, K+ and Ca2+ currents, external application of phospholipase at a low concentration (30 nM) was shown to increase the baseline current in a reversible manner. The augmented response was voltage-dependent and the effect was much greater for negative currents. In the presence of a salt gradient across the membrane (out 40 mM NaCl/in 140 mM CsCl), the current reversal potential revealed a shift in the positive direction typically due to Cl- ion flux through the membrane. External application of a 50 microM concentration of picrotoxin caused a reversible reduction of the phospholipase-induced chloride current. Moreover, no appreciable current block was detected after addition of 50 microM DIDS.
    • Accession Number:
      0 (Anions)
      0 (Chloride Channels)
      0 (Elapid Venoms)
      0 (Ion Channels)
      0 (Membrane Proteins)
      0 (Reptilian Proteins)
      EC 3.1.1.32 (Phospholipases A)
      EC 3.1.1.4 (Oxyuranus scutellatus toxin 2)
      EC 3.1.1.4 (Phospholipases A2)
    • Publication Date:
      Date Created: 19920407 Date Completed: 19920514 Latest Revision: 20190609
    • Publication Date:
      20221208
    • Accession Number:
      10.1016/0167-4889(92)90178-e
    • Accession Number:
      1373076