Hydrolyses the products of EC
2.1.1.77 (protein-L-isoaspartate(D-aspartate) O-methyltransferase), EC
2.1.1.78 (isoorientin 3'-O-methyltransferase), EC
2.1.1.80 (protein-glutamate O-methyltransferase) and EC
2.1.1.100 (protein-S-isoprenylcysteine O-methyltransferase).