Name: Imperatoxin A
Brand: Alomone Labs
SKU: STI-333

Overview

Cat #: STI-333

Alternative Name IpTxa

Lyophilized Powder yes

Origin Synthetic peptide

MW: 3758 Da

Purity: >98% (HPLC)

Form Lyophilized powder.

Effective concentration 10-300 nM.

Sequence GDCLPHLKRCKADNDCCGKKCKRRGTNAEKRCR.

Modifications Disulfide bonds between Cys³-Cys¹⁷, Cys¹⁰-Cys²¹ and Cys¹⁶-Cys³².

Structure

Molecular formula C₁₄₈H₂₅₄N₅₈O₄₅S₆.

CAS No.: 172451-37-5

Activity Imperatoxin A is a strong agonist of ryanodine receptor channels (RyR)¹. Induces voltage- and concentration-dependent subconductance states in both skeletal (RYR1 and RYR3) and cardiac (RYR2) ryanodine receptors by binding to a single, cytosolic accessible site different from the ryanodine binding site. The activating effect is dose-dependent (ED₅₀=10 nM), with fast onset and found fully reversible².

References-Activity

Valdivia, H.H. et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 12185.
El-Hayek, R. et al. (1995) J. Biol. Chem. 270, 28696.

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 Water or 0.9% NaCl solution. Centrifuge all product preparations before use (10000 x g 5 min).

Storage of solutions Store at 4°C for up to 1 week. For longer periods, small aliquots should be stored at -20°C. Avoid multiple freezing and thawing.

References - Scientific background

Valdivia, H.H. et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 12185.
El-Hayek, R. et al. (1995) J. Biol. Chem. 270, 28696.
Zamudio, F. Z. et al. (1997) FEBS Lett. 405, 385.
Gurrola G.B. et al. (1999) J. Biol. Chem. 274, 7879.

Scientific background

Imperatoxin A (IpTxa) is a 33 amino acid natural peptidyl toxin isolated from the venom of scorpion Pandinus imperator. IpTxa interacts specifically and activates the sarcoplasmic reticulum Ca²⁺-release channel of skeletal and cardiac muscle (ryanodine receptor 1 and 2). It reversibly enhances binding of ryanodine to the receptors. The activating effect of IpTxa on skeletal ryanodine receptor is Ca²⁺-dependent, synergized by caffeine, and independent of other modulators of RyRs^1-3.

IpTxa increased the open probability of rabbit skeletal muscle RyRs by increasing the frequency of open events and decreasing the duration of the closed lifetimes.²

IpTxa displays structural homology with an activating segment of the a1 subunit of the skeletal dihydropyridine receptor (II-III loop, segment Glu⁶⁶⁶-Leu⁶⁹⁰) which is putatively the native activator of ryanodine receptor. IpTxa and the segment Glu⁶⁶⁶-Leu⁶⁹⁰ activate RyRs in a similar manner and appear to compete for a common binding site on the ryanodine channel protein⁴. This suggest a common mechanism of IpTxa and dihydropyridine receptor for modulation of RyR⁴.

Target Ryanodine receptors

Peptide Content: 100%

Lyophilized Powder

Imperatoxin-A (#STI-333) is a highly pure, synthetic, and biologically active peptide toxin.

Certificate of Analysis SDS

For research purposes only, not for human use

Last Update: 07/05/2024

Applications

Citations

Product citations

Nesuashvili, C. et al. (2013) Mol. Pharmacol. 83, 1007.
Diaz-Sylvester, P.L. and Copello, J.A. (2009) PLoS ONE 4, e8315.
Porta, M. et al. (2008) Biochim. Biophys. Acta 1778, 2469.

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Imperatoxin A

Overview

Applications

Citations

Specifications

Scientific Background

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