Involved in the anaerobic nitrogen utilization via the assimilation of allantoin. Catalyzes the second stereospecific hydrolysis reaction (deamination) of the allantoin degradation pathway, producing S-ureidoglycolate and ammonia from S-ureidoglycine. (S)-2-ureidoglycine + H2O = (S)-ureidoglycolate + NH4(+) Also able to use Co(2+)). Monomer. By glyoxylate and allantoin under anaerobic conditions. Belongs to the UGHY family.