Maitotoxin: Difference between revisions
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'''Maitotoxin''' or MTX is an extremely potent [[toxin]] produced by ''[[Gambierdiscus toxicus]]'', a [[dinoflagellate]] species |
'''Maitotoxin''' or MTX is an extremely potent [[toxin]] produced by ''[[Gambierdiscus toxicus]]'', a [[dinoflagellate]] species. Maitotoxin is so potent that it has been demonstrated that an [[peritoneum|intraperitoneal]] injection of 0.13 [[microgram|µg]]/kg was lethal in mice.{{Ref|Yokoyama}} Maitotoxin was named from the ciguateric fish ''Ctenochaetus striatus''—called “maito” in [[Tahiti]]—from which maitotoxin was isolated for the first time - later it was shown that maitotoxin is actually produced by ''Gambierdiscus toxicus''. |
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Maitotoxin activates Ca<sup>2+</sup> permeable, non-selective cation channels, leading to an increase in levels of cytosolic Ca<sup>2+</sup> ions. It is thought that maitotoxin leads to the formation of pores on these [[ion channels]]. Ultimately, a [[cell death]] cascade is activated, resulting in [[membrane blebbing]] and eventually [[cell lysis]]. Maitotoxin is known to activate cytosolic calcium-activated proteases calpain-1 and calpain-2, contributing to necrosis {{Ref|Wang}}. The [[toxicity]] of maitotoxin to mice is the highest in nonprotein toxins: the [[Median lethal dose|LD50]] is 50 ng/kg. |
Maitotoxin activates Ca<sup>2+</sup> permeable, non-selective cation channels, leading to an increase in levels of cytosolic Ca<sup>2+</sup> ions. It is thought that maitotoxin leads to the formation of pores on these [[ion channels]]. Ultimately, a [[cell death]] cascade is activated, resulting in [[membrane blebbing]] and eventually [[cell lysis]]. Maitotoxin is known to activate cytosolic calcium-activated proteases calpain-1 and calpain-2, contributing to necrosis {{Ref|Wang}}. The [[toxicity]] of maitotoxin to mice is the highest in nonprotein toxins: the [[Median lethal dose|LD50]] is 50 ng/kg. |
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Revision as of 16:20, 16 March 2009
| File:Maitotoxin.png | |
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| Identifiers | |
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| ECHA InfoCard | 100.227.039 |
CompTox Dashboard (EPA)
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| Properties | |
| C164H256O68S2Na2 | |
| Molar mass | 3422 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Maitotoxin or MTX is an extremely potent toxin produced by Gambierdiscus toxicus, a dinoflagellate species. Maitotoxin is so potent that it has been demonstrated that an intraperitoneal injection of 0.13 µg/kg was lethal in mice.[1] Maitotoxin was named from the ciguateric fish Ctenochaetus striatus—called “maito” in Tahiti—from which maitotoxin was isolated for the first time - later it was shown that maitotoxin is actually produced by Gambierdiscus toxicus.
Maitotoxin activates Ca2+ permeable, non-selective cation channels, leading to an increase in levels of cytosolic Ca2+ ions. It is thought that maitotoxin leads to the formation of pores on these ion channels. Ultimately, a cell death cascade is activated, resulting in membrane blebbing and eventually cell lysis. Maitotoxin is known to activate cytosolic calcium-activated proteases calpain-1 and calpain-2, contributing to necrosis [2]. The toxicity of maitotoxin to mice is the highest in nonprotein toxins: the LD50 is 50 ng/kg.
The molecule itself exists as a system of 32 fused rings. It is notable because it is one of the largest, and most complex, non-protein or non-polysaccharide molecule produced by an organism. Maitotoxin includes 32 ether rings, 22 methyls, 28 hydroxyls, and 2 sulfuric acid esters and has an amphipathic structure. Its structure was established through analysis using nuclear magnetic resonance at Tohoku University, Harvard and the University of Tokyo in combination with mass spectroscopy, and synthetic chemical methods.
References
 | This article has an unclear citation style. (September 2007) |
- ^ Yokoyama, A; et al. (1988). "Some Chemical Properties of Maitotoxin, a Putative Calcium Channel Agonist Isolated from a Marine Dinoflagellate". J. Biochem. 104 (2): 184–187. ISSN: 0021-924X.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Estacion, M and Schilling, WP (2001). "Maitotoxin-induced membrane blebbing and cell death in bovine aortic endothelial cells". BMC Physiology. 1 (2): 2. doi:10.1186/1472-6793-1-2.
{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Murata, M; et al. (2001). "Structure and partial stereochemical assignments for maitotoxin, the most toxic and largest natural non-biopolymer". J. Am. Chem. Soc. 116 (16): 7098–7107. doi:10.1021/ja00095a013.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Sasaki, M; et al. (1996). "The complete structure of maitotoxin, I; Configuration of the C1-C14 side chain". Angew. Chem. Int. Ed. Engl. 35: 1672–1675. doi:10.1002/anie.199616721. ISSN: 0570-0833.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Kishi, Y (1998). "Complete structure of maitotoxin". Pure & Appl. Chem. 70 (2): 339–344. doi:10.1351/pac199870020339.
- ^ Jones, Matland (2004). Organic Chemistry, Third Edition. W. W. Norton & Company. ISBN 978-0393924084.
- ^ Wang, K.; et al. (1996). "Maitotoxin induces calpain activation in SH-SY5Y neuroblastoma cells and cerebrocortical cultures". Arch. Biochem. Biophys. 331: 208–214. doi:10.1006/abbi.1996.0300. ISSN: 0003-9861.
{{cite journal}}: Explicit use of et al. in:|author=(help)