Melittin

Definition

A 26-amino-acid cationic peptide that constitutes the primary active component of honeybee (Apis mellifera) venom, responsible for the immediate pain, inflammation, and cytolytic effects of envenomation. Melittin disrupts cell membranes by forming barrel-stave pores, triggering phospholipase A2 activation and downstream inflammatory cascades. It also exhibits broad antimicrobial activity and is widely studied as a model for membrane-active peptides and as a potential therapeutic lead.

Etymology

From Latin mel, mellis (honey), referring to its source in honeybee venom.

Example

Melittin concentrations in honeybee venom range from 40–60% of dry venom mass; a single sting delivers approximately 50–140 μg, sufficient to cause localized hemolysis and pain through mast cell degranulation and bradykinin release.

Synonyms

• melittin peptide
• bee venom peptide

Related Terms

• apamin
• phospholipase A2
• mastoparan
• venom gland
• envenomation
• membrane permeabilization
• Apis mellifera

Usage Notes

Distinguish from 'melittin-like' peptides in other hymenopterans; melittin proper is specific to Apis species. The term refers to the purified peptide, not whole venom. Concentrations vary seasonally and with worker age. Research applications often use synthetic or recombinant melittin rather than extracted venom to avoid contaminating allergens.