Apitoxin or bee venom is the venom produced by the honey bee. It is a cytotoxic and hemotoxic bitter colorless liquid containing proteins, which may produce local inflammation. It may have similarities to sea nettle toxin. Bee venom is a complex mixture of proteins and smaller molecules. The main component is melittin, which amounts to 52% of venom peptides One of the main allergens is phospholipase A2, which amounts to 12% and is an enzyme that catalyzes the hydrolysis of phospholipids, causing degradation of cell membranes. Adolapin contributes 2–5% of the peptides. Further protein components include apamin (2%), a neurotoxin, hyaluronidase (2%), which dilates blood vessels, increasing their permeability and facilitating the spread of the venom, mast cell degranulating peptide (2%), tertiapin, and secapin. Small molecules in bee venom include histamine (0.1–1%), dopamine and noradrenaline. Mark Crislip, a practicing infectious disease specialist, examined the claims that bee venom can treat arthritis. He was unable to "find a clean, i.e., a non-TCPM based, randomized, placebo-controlled study of bee venom in humans for the treatment [of] arthritis." Apitoxins are under preliminary research for their potential biological effects, such as in cancer.