Rather more predominant for the cleavage of aryl- than for alkyl-hydantoin derivatives. The stereoselectivity of this enzyme depends on the substrate used for bioconversion: strictly L-selective for the cleavage of D,L-5-indolylmethylhydantoin, but D-selective for the hydrolysis of D,L-methylthioethylhydantoin. Binds 2 Zn(2+) ions per subunit. Homotetramer. Carboxylation allows a single lysine to coordinate two zinc ions. Belongs to the metallo-dependent hydrolases superfamily. Hydantoinase/dihydropyrimidinase family.