May be involved in the asymmetric conversion of racemic 5-substituted hydantoins to the corresponding L-amino acids. Catalyzes specifically the conversion of N-carbamoyl-L-amino acids to free L-amino acids in an irreversible reaction. N-carbamoyl-L-methionine is the best substrate. HyuC of R.meliloti is the first L-N-carbamoylase that hydrolyzes N-carbamoyl-L-tryptophan as well as N-carbamoyl-L-amino acids with aliphatic substituents. an N-carbamoyl-L-alpha-amino acid + 2 H(+) + H2O = an L-alpha-amino acid + CO2 + NH4(+) Binds 2 divalent metal cations per subunit. Ni(2+), Mn(2+), Co(2+) and Fe(2+) ions greatly increase hydrolase activity. Strongly inhibited by Hg(2+), Cu(2+), Zn(2+), Pb(2+) and Fe(3+) ions, and slightly inhibited by Na(+) and K(+) ions. Beta-mercaptoethanol and 5,5'-dithiobis-(2-nitrobenzoic acid)(DTNB) cause 34% and 42% inhibition, respectively. kcat is 91.66 sec(-1) for formyl-L-methionine as substrate (at 40 degrees Celsius). kcat is 66.84 sec(-1) for N-acetyl-L-methionine as substrate (at 40 degrees Celsius). kcat is 16.9 sec(-1) for N-carbamoyl-L-valine as substrate (at 40 degrees Celsius). kcat is 14.46 sec(-1) for N-carbamoyl-L-methionine as substrate (at 40 degrees Celsius). kcat is 13.55 sec(-1) for N-carbamoyl-L-cysteine as substrate (at 40 degrees Celsius). kcat is 4.26 sec(-1) for N-carbamoyl-L-phenylalanine as substrate (at 40 degrees Celsius). kcat is 2.59 sec(-1) for N-carbamoyl-L-alanine as substrate (at 40 degrees Celsius). kcat is 1.52 sec(-1) for N-carbamoyl-L-glutamic acid as substrate (at 40 degrees Celsius). kcat is 0.30 sec(-1) for N-carbamoyl-L-tyrosine as substrate (at 40 degrees Celsius). kcat is 0.15 sec(-1) for N-carbamoyl-L-tryptophan as substrate (at 40 degrees Celsius). Optimum pH is 8. Optimum temperature is 60 degrees Celsius. Homodimer. Belongs to the peptidase M20 family.