The smallest known neurotoxic peptide, and the defining pharmacological probe for SK potassium channels.
Also known as: apamine
Part of the Foundational & therapeutic peptides cluster
Overview
Apamin is an 18-amino-acid neurotoxic peptide from honeybee venom, cross-linked by two disulfide bonds into a compact fold. It is the classic selective blocker of small-conductance calcium-activated potassium (SK) channels, so it is used throughout neuroscience to dissect the afterhyperpolarization that follows neuronal firing. This page is educational and not medical advice.
Source & context
Biological / chemical source: Honeybee venom (Apis mellifera)
Primary research or clinical context: Widely used pharmacological research tool for SK-channel physiology
SK-channel probe
By blocking SK channels, apamin removes part of the potassium current that normally repolarizes neurons after an action potential, increasing excitability. Its high selectivity made it the reference tool for identifying SK channels and studying their role in rhythmic firing, synaptic plasticity and muscle activity.
Context and cautions
Apamin makes up a few percent of dry bee venom and is a potent neurotoxin, so it is handled strictly as a laboratory reagent. Researchers have examined SK-channel modulation in memory and movement disorders, but such work is exploratory. This page provides educational background only.
Sequence
One-letter sequence commonly cited for Apamin (educational; isoforms and modifications may differ):
CNCKAPETALCARRCQQH
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
FAQ about Apamin
What is Apamin?+
Apamin is an 18-amino-acid neurotoxic peptide from honeybee venom, cross-linked by two disulfide bonds into a compact fold. It is the classic selective blocker of small-conductance calcium-activated potassium (SK) channels, so it is used throughout neuroscience to dissect the afterhyperpolarization that follows neuronal firing. This page is educational and not medical advice.
Is Apamin an approved medicine?+
Apamin is discussed here as a research / educational topic. Widely used pharmacological research tool for SK-channel physiology. This is not medical advice.
What is the typical length of Apamin?+
Apamin is commonly described as approximately 18 amino acids (Bee-venom neurotoxin peptide).