Imperatoxin A
- 貨號 Cat. No.
- I-300
- 規格 Size
- 5 μg 5x5 μg
Description
Imperatoxin A
Ryanodine Receptor Modulator
| Product#: | I-300 |
| Sizes: |
| 5 mg |
| 5 x 5 mg |
| M.W.: | 3758 |
| Purity: | >99% |
| Bioassay: |
Imperatoxin (I-300) modulates Spark- and Ember-like Elementary Ca2+ Release (ECRE) events in rat cardiomyocyte cells. |
 |
Cardiomyocite cell culture prepared from the heart of 2 day old rat pups were loaded with 4 mM fluo-3 AM and the Ca2+ trace was measured before and after stimulation with 300nM Imperatoxin. The picture show the ECRE events (in the same microscopic field) before (A) and after (B) Imperatoxin treatment. |
| References: |
1. | Valdivia, H.H. et al. (1992) Proc. Natl. Acad. Sci. USA. 89, 12185. |
2. | El-Hayek, R. et al. (1995) J. Biol. Chem 270, 28696. |
3. | Zamudio, F. Z. et al. (1997) FEBS Lett. 405, 385. |
4. | Georgina B. et al. (1999) J. Biol. Chem. 274, 7879. |
Imperatoxin A (IpTxa) is a 33 amino acid natural peptidyl toxin isolated from the venom of scorpion Pandinus imperator. IpTxa interactsspecifically 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 thereceptors. The activating effect of IpTxa on skeletal ryanodine receptor is Ca 2+-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 protein.4 Thissuggest a common mechanism of IpTxa and dihydropyridine receptor for modulation of RyR.4
Alomone Labs is pleased to offer Imperatoxin A a syntetic toxin identical with the natural toxin from the Pandinus imperator venum.