Catalyzes the catabolism of the allantoin degradation intermediate (S)-ureidoglycolate, generating urea and glyoxylate. Involved in the utilization of allantoin as secondary nitrogen source when primary sources are limiting. (S)-ureidoglycolate = glyoxylate + urea Optimum pH is 7.3. Nitrogen metabolism; (S)-allantoin degradation. Homodimer. Subject to nitrogen catabolite repression. Belongs to the ureidoglycolate lyase family. This enzyme was also named ureidoglycolate hydrolase in the literature. However, this is the recommended name of another enzyme (EC 3.5.1.116) acting on ureidoglycolate. To make the distinction between ammonia- or urea-releasing activities from ureidoglycolate, the use of this ambiguous name is deprecated.