Melittin is the principal active component of apitoxin

Apitoxin

Apitoxin, or honey bee venom, is a bitter colorless liquid. The active portion of the venom is a complex mixture of proteins, which causes local inflammation and acts as an anticoagulant. The venom is produced in the abdomen of worker bees from a mixture of acidic and basic secretions. Apitoxin...

 (bee venom) and is a powerful stimulator of phospholipase A2

Phospholipase A2

Phospholipases A2 are enzymes that release fatty acids from the second carbon group of glycerol. This particular phospholipase specifically recognizes the sn-2 acyl bond of phospholipids and catalytically hydrolyzes the bond releasing arachidonic acid and lysophospholipids...

. Melittin is a peptide

Peptide

Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...

 consisting of 26 amino acids with the sequence GIGAVLKVLTTGLPALISWIKRKRQQ.

Biological effects

Melittin also exhibits potent anti-microbial activity. For example, melittin has been shown to exert "profound inhibitory effects" on Borrelia burgdorferi

Borrelia burgdorferi

Borrelia burgdorferi is a species of Gram negative bacteria of the spirochete class of the genus Borrelia. B. burgdorferi is predominant in North America, but also exists in Europe, and is the agent of Lyme disease....

, the bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 that causes lyme disease

Lyme disease

Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...

. Melittin has also been shown to kill the yeast Candida albicans

Candida albicans

Candida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...

and to suppress Mycoplasma hominis

Mycoplasma hominis

Mycoplasma hominis is a strain of bacteria present in the vagina. It may or may not belong to the normal vaginal flora. It is also believed to be a cause of pelvic inflammatory disease. If so, it would be only one of many known causes....

and Chlamydia trachomatis

Chlamydia trachomatis

Chlamydia trachomatis, an obligate intracellular human pathogen, is one of three bacterial species in the genus Chlamydia. C. trachomatis is a Gram-negative bacteria, therefore its cell wall components retain the counter-stain safranin and appear pink under a light microscope.The inclusion bodies...

infections.

At Washington University School of Medicine in St. Louis, very small nanite "nanobee" devices are being developed to carefully deliver melittin, which is known to disrupt cellular walls and thus destroy cells, to tumor cells in animals.

Melittin modifies the permeability of the red cell membrane.
http://www.ncbi.nlm.nih.gov/pubmed/4057243

Melittin in Art

Artist and scientist Julian Voss-Andreae

Julian Voss-Andreae

Julian Voss-Andreae is a German sculptor living and working in the U.S.Voss-Andreae started out as a painter and later studied experimental physics at the universities of Berlin, Edinburgh and Vienna...

has created a sculpture based on the structure of melittin, which he mentions in a talk about his work.