Proteolytically removes the C-terminal three residues of farnesylated A-factor mating pheromone. Also acts to cleave the N-terminal extension of the pheromone. Does not act on Ras. The peptide bond hydrolyzed can be designated -C-|-A-A-X in which C is an S-isoprenylated cysteine residue, A is usually aliphatic and X is the C-terminal residue of the substrate protein, and may be any of several amino acids. Binds 1 zinc ion per subunit. Present with 19600 molecules/cell in log phase SD medium. Belongs to the peptidase M48A family.