Possesses in vitro carboxypeptidase activity against the C-terminal arginine and lysine residues. Involved in the maturation of CLE19. Removes the C-terminal arginine residue of CLE19 proprotein. The cleavage of the C-terminal arginine residue is necessary for CLE19 activity in vivo. Is not involved in generating active CLV3 (PubMed:24118638). Is not involved in CLE19 or CLV3 perception (PubMed:12932329, PubMed:24118638). Binds 1 zinc ion per subunit. A number of isoforms are produced. According to EST sequences. Expressed in roots, shoots, leaves, flowers and siliques. Belongs to the peptidase M14 family.