Leucine aminopeptidase (LAP)

Leucine aminopeptidase is a **zinc-dependent metallopeptidase** that removes N-terminal amino acid residues (especially leucine) from peptides and proteins. It is present in nearly all forms of life, including animals, plants, and microbes, and is primarily cytosolic in mammals but may be targeted to other compartments in plants and bacteria. LAPs most efficiently catalyze the hydrolysis of peptides with N-terminal leucine but can act on various amino acids, contributing to general protein turnover and specific peptide maturation processes. Structurally, LAPs exist as **hexamers with active sites lining a central cavity** and require divalent metal ions (usually Zn²⁺, Mn²⁺, or Mg²⁺) for activity. They are involved in fundamental cellular functions such as peptide catabolism, antigen processing (including final trimming of antigenic peptides for MHC I presentation), and repair or turnover of oxidatively damaged proteins. LAPs also have additional roles such as transcriptional regulation and stress response (notably in plants and bacteria), and may underlie certain disease processes including cancer and infectious diseases[1][3][4][7].

Other names

Leucyl aminopeptidaseLAPLeucyl peptidasePeptidase SCytosol aminopeptidaseCathepsin IIIL-leucine aminopeptidaseLeucinaminopeptidaseLeucinamide aminopeptidaseFTBL proteinAminopeptidase IIAminopeptidase IIIAminopeptidase I

Enzyme inhibition (drugs such as bestatin and amastatin inhibit LAP activity by binding to the active site and blocking peptide cleavage)[3][5]