LEAP-2 is a member of the liver-expressed antimicrobial peptide (LEAP) family. It is a 40-amino acid peptide cleaved from a 77-amino acid precursor by a furin-like endoprotease. The LEAP-2 peptide is rich in cysteine and contains two disulfide bonds formed by cysteine residues at the 1-3 and 2-4 positions. Highly conserved among mammals, LEAP-2 is expressed by hepatocytes in the liver, as well as in the small intestine and central nervous system.
Originally identified as an antimicrobial peptide, LEAP-2 plays a role in the innate immune system by fighting bacterial infections. It has also been implicated in inflammatory processes, particularly in patients with rheumatoid arthritis, an autoimmune disease. Recent studies have shown that LEAP-2 has an anorexigenic effect and acts as a ghrelin antagonist. In addition, plasma levels of LEAP-2 are elevated in obese patients.