Other · Disulphide-rich inward-rectifier potassium-channel blocker
Tertiapin
Also known as TPN
A 21-residue honeybee venom peptide used to probe selected inward-rectifier potassium channels, including Kir1.1 and Kir3 assemblies.
- Length
- 21 amino acids
- Half-life
- Not well characterised
- Mechanism
- Tertiapin binds at the extracellular pore of susceptible inward-rectifier potassium channels, notably Kir1.1 and Kir3.1/Kir3.4 assemblies, and obstructs potassium conduction. Channel sensitivity depends on pore sequence and subunit composition.
- Studied in
- Recombinant channel assays, renal epithelial preparations and animal cardiac-cell models use tertiapin to investigate Kir1.1 and G-protein-gated inward-rectifier currents.
About Tertiapin
Tertiapin was isolated from Apis mellifera venom during biochemical studies of minor honeybee venom constituents in the 1970s. It comprises 21 amino acids stabilised by two disulphide bonds and has an amidated C-terminus. Its compact architecture differs from the larger, three-disulphide scorpion toxins commonly used against voltage-gated potassium channels. Native tertiapin contains methionine at position 13, an oxidation-sensitive residue that is important when distinguishing the original peptide from modified research analogues.
Subsequent electrophysiological work established tertiapin as an extracellular blocker of selected inward-rectifier potassium channels. Prominent targets include the renal outer medullary potassium channel Kir1.1 and the Kir3.1/Kir3.4 combination studied in cardiac preparations. It is not a universal Kir inhibitor, and channel assembly strongly influences responsiveness. Laboratory applications therefore pair toxin sensitivity with molecular identification, expression controls or complementary blockers when separating inward-rectifier currents from other conductances in a mixed cellular preparation.
Laboratory notes
- Monitor oxidation during storage and assay preparation, particularly modification of methionine 13; use supplier-validated stability conditions.
- Verify whether the material is native tertiapin or the M13Q analogue tertiapin-Q, as these are distinct reference compounds.
- For research use only. Confirm the expressed Kir subunits and use appropriate toxin-handling precautions.
Storage and reconstitution basics: storage guide.
Questions about Tertiapin
Is tertiapin the same compound as tertiapin-Q?
No. Tertiapin-Q replaces methionine 13 with glutamine to reduce susceptibility to oxidation at that position.
Which channel names correspond to its main research targets?
Kir1.1 is also called ROMK. Kir3 channels are commonly called GIRK channels, with Kir3.1/Kir3.4 forming a well-studied tertiapin-sensitive assembly.
Can tertiapin identify every inward-rectifier current?
No. Sensitivity varies substantially across the Kir family, so absence of inhibition does not exclude an inward-rectifier contribution.
Is Tertiapin for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.