Involved in the asymmetric conversion of racemic 5-substituted hydantoins to the corresponding L-amino acids. Catalyzes the conversion of N-carbamoyl-L-methionine to L-methionine in an irreversible reaction. Unable to convert N-carbamoyl-D-methionine. an N-carbamoyl-L-alpha-amino acid + 2 H(+) + H2O = an L-alpha-amino acid + CO2 + NH4(+) Binds 2 divalent metal cations per subunit. Belongs to the peptidase M20 family.