Carboxypeptidase M (CPM) belongs to the peptidase M14 family, and exists in cell membrane. The protein binds 1 zinc ion per subunit, and cleavage of C-terminal arginine or lysine residues from polypeptides. CPM specifically removes C-terminal basic residues (Arg or Lys) from peptides and proteins. It is believed to play important roles in the control of peptide hormone and growth factor activity at the cell surface, and in the membrane-localized degradation of extracellular proteins.