Cyclic amide hydrolase of unknown substrate specificity. Catalyzes the hydrolytic ring-opening of a cyclic amide. Does not act on cyanuric acid nor barbituric acid. Homotetramer. The monomer structure is formed from three repeating units (RUs) that share the same structure as one another. The monomer and the active site possess nearly threefold rotational symmetry, to the extent that the active site possesses three potential Ser-Lys catalytic dyads, but one of the 3 active site surfaces varies in composition suggesting it is involved in confering substrate specificity. Belongs to the cyclic amide hydrolase (CyAH) family.