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A Blocker of Small Conductance Ca2+-Activated K+ Channels (SK Type) Conjugated to Biotin

Cat #: STA-200-B
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Synthetic peptide
    MW: 2367 Da
    Purity: >98% (HPLC)
    Effective concentration 1-50 nM.
    Modifications Disulfide bonds between Cys1-Cys11, and Cys3-Cys15. His18 - C-terminal amidation.
    Label LC-Biotin. The extent of labeling is 1 molecule of biotin per molecule of Apamin.
    Activity Apamin is a blocker of voltage-independent Ca2+-activated K(SK) channels1.
    1. Shahidi, S. et al. (1993) Biochim. Biophys. Acta 1157, 74.
    Shipping and storage Shipped at room temperature. Product as supplied can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Solubility Any aqueous buffer. Centrifuge all product preparations before use (10000 x g 5 min).
    Storage of solutions Up to two weeks at 4°C or three months at -20°C.
    Our bioassay
    • Alomone Labs Apamin-Biotin blocks rat SK2 channels stably transfected in HEK293T cells.
      Alomone Labs Apamin-Biotin blocks rat SK2 channels stably transfected in HEK293T cells.
      A. Time course of Apamin-Biotin (#STA-200-B) action on SK2 channels. Current amplitudes were plotted as a function of time. Membrane potential was held at -80 mV and cells were stimulated by a 150 ms voltage ramp from -120 mV to +60 mV every 10 sec. 1 nM, 10 nM and 50 nM Apamin-Biotin were perfused during 120 sec as indicated by the bar at 0 mV. B. Superimposed examples of SK2 channel current in the absence (control, black) and presence of 1 nM (green), 10 nM (red) and 50 nM (blue) Apamin-Biotin (taken from the experiment in A).
    • Alomone Labs Apamin-Biotin stains rat parietal cortex.
      Alomone Labs Apamin-Biotin stains rat parietal cortex.
      Lightly-fixed sections of rat brain were incubated overnight with Apamin-Biotin (#STA-200-B) (1 nM) followed by 45 minutes fixation in cold 4% paraformaldehyde and followed by the addition of streptavidin labeled with ATTO-594. Most of the staining is seen in pyramidal neurons (horizontal arrows) as well as in astrocyte-like processes (vertical arrows).
    References - Scientific background
    1. Gauldie, J. et al. (1976) Eur. J. Biochem61, 369.
    2. Logsdon, N.J. et al. (1997) J. Biol. Chem272, 32723.
    3. Shah M. and Haylett D.G. (2000) Br. J. Pharm. 129, 627.
    4. Strobaek D. et al. (2000) Br. J. Pharm. 129, 991.
    5. Barfod, E.T. et al. (2001) Am. J. Physiol. 280, C836.
    6. Desai, R. et al. (2000) J. Biol. Chem275, 39954.
    7. Hosseini, R. et al. (2001) J. Physiol. 535, 323.
    8. Kong, I.D. et al. (2000) Am. J. Physiol. 278, C352.
    9. Nagayama, T. et al. (2000) Am. J. Physiol279, R1731.
    Scientific background

    Apamin is a natural peptide isolated and purified from Apis mellifera bee venom. Apamin blocks small conductance Ca2+-activated K+ channels (SK). It is specific for the SK1-3 isoforms, but ineffective in blocking other calcium activated K+ channels2. In mammalian cell lines, Apamin blocks expressed hSK1 with an IC50 of ~10 nM3, rSK1 and rSK2 with IC50 of ~3 and <1 nM respectively4 and liver rSK3 with IC50<1 nM.5 In Jurkat T-cells, 5 nM of Apamin blocks 70% of hSK2 currents.6

    Blocking these channels with Apamin slows down neuronal activity after hyperpolarization7, as well as smooth muscle contraction8 and catecholamine secretion in adrenal glands.Electrophysiology application of long (~400 ms) voltage ramps, covering the whole physiological range (-160 to +40 mV), in the whole cell patch-clamp or voltage clamp configurations, before and after bath perfusion of the drug, allows the detection of the blocked channel currents (by comparison).1

    Target KCa2 K+ channels
    Peptide Content: 100%
    Last update: 02/01/2022

    Apamin-Biotin (#STA-200-B) is a highly pure, synthetic, and biologically active conjugated peptide toxin.

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    For research purposes only, not for human use
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