LAP3(Leucine aminopeptidase 3) is also named as LAPEP,PEPS(peptidase S) and belongs to the peptidase M17 family. It can catalyzes the removal of unsubstituted N-terminal amino-acids from various peptides and be presumably involved in the processing end regular turnover of intracellular proteins. PEPS is found in a wide variety of tissues and cultured cells but not in red cells and skin. The enzyme can utilize several di-,tri-,and tetrapeptides as substrates and is the slowest migrating of the peptidases after electrophoresis.. LAP3 has two isoform with MW of 52 and 56 kDa.