This family consists of several mammalian liver-expressed antimicrobial peptide 2 (LEAP-2) sequences. LEAP-2 is a cysteine-rich, and cationic protein. LEAP-2 contains a core structure with two disulfide bonds formed by cysteine residues in relative 1-3 and 2-4 positions. LEAP-2 is synthesised as a 77-residue precursor, which is predominantly expressed in the liver and highly conserved among mammals. The largest native LEAP-2 form of 40 amino acid residues is generated from the precursor at a putative cleavage site for a furin-like endoprotease. In contrast to smaller LEAP-2 variants, this peptide exhibits dose-dependent antimicrobial activity against selected microbial model organisms [1]. The exact function of this family is unclear.

1: Isolation and biochemical characterization of LEAP-2, a novel blood peptide expressed in the liver. Krause A, Sillard R, Kleemeier B, Kluver E, Maronde E, Conejo-Garcia JR, Forssmann WG, Schulz-Knappe P, Nehls MC, Wattler F, Wattler S, Adermann K; Protein Sci 2003;12:143-152. PMID:12493837