Endopeptidase which proteolytically removes the C-terminal three residues of farnesylated peptides containing the CAAX motif where C is cysteine, A is an aliphatic amino acid and X is any amino acid. Cleaves the CAAX motif C-terminal to both P1 and P1' positions. Hydrolysis depends on a farnesylated cysteine residue and no activity is shown towards geranylgeranylated peptides. Activity is unaffected by metalloprotease inhibitors 5 mM EDTA and 5 mM Zn(2+). Activity partially inhibited by 1,10-phenanthroline and 1,7-phenanthroline. kcat is 0.175 sec(-1) for peptide substrate DABCYL-ARSGAKASGC(farnesyl)LVS-EDANS. Belongs to the peptidase U48 family.