| Melittin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 Melittin | |||||||||
| Identifiers | |||||||||
| Symbol | Melittin | ||||||||
| Pfam | PF01372 | ||||||||
| InterPro | IPR002116 | ||||||||
| SCOP2 | 2mlt /SCOPe /SUPFAM | ||||||||
| TCDB | 1.C.18 | ||||||||
| OPM superfamily | 151 | ||||||||
| OPM protein | 2mlt | ||||||||
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| Identifiers | |
|---|---|
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.157.496 |
| MeSH | Melitten |
| UNII | |
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| Properties | |
| C131H229N39O31 | |
| Molar mass | 2846.46266 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Melittin is the main component (40–60% of the dry weight) and the major pain-producing substance of honeybee (Apis mellifera)venom. Melittin is a basicpeptide consisting of 26amino acids.[2]
The principal function of melittin as a component ofbee venom is to cause pain and destruction of tissue of intruders that threaten a beehive.[citation needed] However, melittin isexpressed, not only in the venom gland, but also in other tissues when the bee is infected with various pathogens.[citation needed] The over-expression of melittin (as well as secapin, another venom molecule) in infected honey bees may indicate that it plays a role in theimmune response of bees toinfectious diseases.[3]
Melittin is a smallpeptide with nodisulfide bridge; theN-terminal part of themolecule is predominantlyhydrophobic and theC-terminal part ishydrophilic and stronglybasic. In water, it forms atetramer, but it also can spontaneously integrate itself into cell membranes.[4]
Injection of melittin into animals and humans causes pain sensations. It has strong surface effects on cell membranes, causing pore formation inepithelial cells and the destruction ofred blood cells. Melittin also activatesnociceptor (pain receptor) cells through a variety of mechanisms.[2]
Melittin can open thermal nociceptorTRPV1 channels viacyclooxygenase metabolites, resulting in depolarization of nociceptor cells. The pore-forming effects in cells cause the release of pro-inflammatory cytokines. It also activatesG-protein-coupled receptor-mediated opening oftransient receptor potential channels. Finally, melittin up-regulates the expression ofNav1.8 andNav1.9 sodium channels in nociceptor cell, causing long-term action-potential firing and pain sensation.[2]
Melittininhibitsprotein kinase C, Ca2+/calmodulin-dependent proteinkinase II,myosinlightchain kinase, and Na+/K+-ATPase (synaptosomal membrane). Melittinblockstransport pumps such as the Na+-K+-ATPase and the H+-K+-ATPase.[2]
Melittin is the main compound in bee venom, accounting for its potentiallethality, caused by ananaphylactic reaction in some people.[5] At the sites of multiple stings, localized pain, swelling, andskin redness occur, and if bees are swallowed, life-threatening swelling of thethroat and respiratory passages may develop.[5]
Bee venom therapy has been used intraditional medicine for treating various disorders,[6] although its non-specifictoxicity has limitedscientific research on its potential effects.[7]
